Overexpression of p53 protein and outcome of patients treated with chemoradiation for carcinoma of the anal canal
1999; Wiley; Volume: 85; Issue: 6 Linguagem: Inglês
10.1002/(sici)1097-0142(19990315)85
ISSN1097-0142
AutoresSteven R. Bonin, T F Pajak, Anthony H. Russell, Lawrence R. Coia, Kristie J. Paris, Marshall S. Flam, Ed R. Sauter,
Tópico(s)Diagnosis and treatment of tuberculosis
ResumoCancerVolume 85, Issue 6 p. 1226-1233 Original ArticleFree Access Overexpression of p53 protein and outcome of patients treated with chemoradiation for carcinoma of the anal canal A report of randomized trial RTOG 87-04 Steven R. Bonin M.D., Corresponding Author Steven R. Bonin M.D. Fox Chase Cancer Center, Philadelphia, PennsylvaniaDepartment of Radiation Oncology, St. Vincent Hospital, 2001 W. 86th Street, Indianapolis, IN 40970.===Search for more papers by this authorThomas F. Pajak Ph.D., Thomas F. Pajak Ph.D. Radiation Therapy Oncology Group (RTOG) Statistical Unit, American College of Radiology, Philadelphia, PennsylvaniaSearch for more papers by this authorAnthony H. Russell M.D., Anthony H. Russell M.D. Radiation Oncology Center, Sacramento, CaliforniaSearch for more papers by this authorLawrence R. Coia M.D., Lawrence R. Coia M.D. Fox Chase Cancer Center, Philadelphia, PennsylvaniaSearch for more papers by this authorKristie J. Paris M.D., Kristie J. Paris M.D. James Graham Brown Cancer Center, Louisville, KentuckySearch for more papers by this authorMarshall S. Flam M.D., Marshall S. Flam M.D. Saint Agnes Cancer Center, Fresno, CaliforniaSearch for more papers by this authorEd R. Sauter M.D., Ed R. Sauter M.D. Fox Chase Cancer Center, Philadelphia, PennsylvaniaSearch for more papers by this author Steven R. Bonin M.D., Corresponding Author Steven R. Bonin M.D. Fox Chase Cancer Center, Philadelphia, PennsylvaniaDepartment of Radiation Oncology, St. Vincent Hospital, 2001 W. 86th Street, Indianapolis, IN 40970.===Search for more papers by this authorThomas F. Pajak Ph.D., Thomas F. Pajak Ph.D. Radiation Therapy Oncology Group (RTOG) Statistical Unit, American College of Radiology, Philadelphia, PennsylvaniaSearch for more papers by this authorAnthony H. Russell M.D., Anthony H. Russell M.D. Radiation Oncology Center, Sacramento, CaliforniaSearch for more papers by this authorLawrence R. Coia M.D., Lawrence R. Coia M.D. Fox Chase Cancer Center, Philadelphia, PennsylvaniaSearch for more papers by this authorKristie J. Paris M.D., Kristie J. Paris M.D. James Graham Brown Cancer Center, Louisville, KentuckySearch for more papers by this authorMarshall S. Flam M.D., Marshall S. Flam M.D. Saint Agnes Cancer Center, Fresno, CaliforniaSearch for more papers by this authorEd R. Sauter M.D., Ed R. Sauter M.D. Fox Chase Cancer Center, Philadelphia, PennsylvaniaSearch for more papers by this author First published: 19 November 2000 https://doi.org/10.1002/(SICI)1097-0142(19990315)85:6 3.0.CO;2-BCitations: 35AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract BACKGROUND Despite encouraging results with chemoradiation as the primary means of managing carcinoma of the anal canal, approximately 20% of patients will develop a local recurrence. This study examined the prognostic significance of p53 nuclear protein overexpression in the pretreatment biopsies of patients treated with chemoradiation for epidermoid carcinoma of the anal canal. METHODS All patients were treated in a prospective, randomized Radiation Therapy Oncology Group trial (RTOG 87-04) in which radiotherapy to the pelvis was compared with concurrent 5-fluorouracil (5-FU) or 5-FU and mitomycin-C. Formalin fixed, paraffin embedded blocks or unstained slides from the pretreatment biopsies of 64 patients were obtained from referring institutions and evaluated immunohistochemically with the polyclonal p53 antibody CM-1. A multivariate analysis was conducted to analyze overexpression of p53 in terms of locoregional control, no evidence of disease (NED), and overall survival. RESULTS p53 protein was overexpressed in 48.4% of the cases. Although not statistically significant, there was a trend for patients whose tumors overexpressed p53 to have inferior locoregional control (52% vs. 72%, P = 0.13), NED survival (52% vs. 68%, P = 0.27), and absolute survival (58% vs. 78%, P = 0.14). Of all the pretreatment factors analyzed, only International Union Against Cancer stage was predictive of outcome in multivariate analysis. Among those patients whose tumors overexpressed p53, there was a trend toward improved outcome in the arm that received 5-FU and mitomycin-C compared with the arm that received 5-FU only. CONCLUSIONS Overexpression of the p53 protein may be associated with inferior outcome for patients managed with definitive chemoradiation for epidermoid carcinoma of the anal canal. Cancer 1999;85:1226–33. © 1999 American Cancer Society. Historically, squamous cell carcinoma (SCC) of the anal canal has been managed by abdominoperineal resection (APR). Because this extensive procedure results in a permanent colostomy, an anus-preserving approach utilizing initial chemoradiation with surgical salvage has been the primary mode of management since the initial reports of Nigro, Flam, and others in the early 1980s.1-3 Primary chemoradiation results in sustained complete response rates of 75–85%, justifying its use as the standard of care for patients with anal carcinoma. Unfortunately, most patients with tumors that fail to respond to chemoradiation will die of their disease.4, 5 It is therefore important to determine which pretreatment factors are predictive of patients' responses to chemoradiation. This could help the clinician identify those patients more appropriately managed by a more intensive course of chemoradiation or by a primary surgical approach. To date, only American Joint Committee on Cancer (AJCC) or International Union Against Cancer (UICC) stage has been predictive of outcome for patients treated with chemoradiation.6-10 A potential prognostic factor is mutation of the p53 tumor suppressor gene. The importance of p53 in the development of malignancy is supported by the observation that mutation of p53 is the most common single mutation observed in human cancers.11 Although such mutations may merely result in loss of the tumor suppressor function of p53, there is some evidence that mutated p53 can behave like an oncogene, thereby inducing malignant transformation.12, 13 The purpose of our study was to determine whether p53 mutation (and the resultant protein overexpression) was a prognostic factor in patients with carcinoma of the anal canal treated with definitive chemoradiation on the prospective, randomized intergroup trial RTOG 87-04. Identification of a subgroup of patients with a sufficiently poor prognosis following standard chemoradiation may be justification for more aggressive treatment in that population. MATERIALS AND METHODS Diagnostic biopsy tissue blocks (or unstained slides from those blocks) were retrospectively obtained from the referring institutions for 80 of the 310 patients treated prospectively with chemoradiation between August 1988 and December 1991 for epidermoid carcinoma of the anal canal on the Phase III protocol RTOG 87-04. The principal investigator (S.R.B.) personally called each institution that had enrolled patients on RTOG 87-04. For a variety of reasons (logistical, technical, etc.), we were able to collect blocks or slides of tissue from 80 of the 310 patients enrolled. After exclusion of specimens in which epidermoid carcinoma could not be identified in the material submitted to us, 68 patients were potentially available (all patients in the trial had to have confirmed anal carcinoma; we were simply unable to verify the histologic presence of cancer in the blocks or slides that we received). Four of them failed to reach eligibility criteria for the treatment protocol and have subsequently been excluded from the database of this trial. (We requested specimens from all patients originally registered on RTOG 87-04, and we later learned that these four patients were among a group of patients who were deemed ineligible for the protocol for a variety of reasons. These patents were never included in the database for RTOG 87-04.) Thus, 64 patients were analyzed. The median patient age was 65 years. Twenty-one of the patients were male and 43 were female. The 1978 UICC staging system was employed in this study so that results could be compared with those from older trials.10 Briefly, in this system, T1 and T2 are defined as involving less than or greater than one-third of the circumference of the anal canal, respectively. Classification as T3 requires extension to rectum or skin, whereas T4 represents involvement of adjacent structures such as the bladder, urethra, or vagina.10 The clinical T classifications were T1 in 7 cases, T2 in 23, T3 in 26, and T4 in 8. Eleven had clinical or pathologic evidence of lymph node involvement, whereas 53 were N0 (no lymph node involvement). Histologically, 11 were squamous cell carcinoma and 53 were baseloid squamous or other. Table 1 contains the patient characteristics of the population studied. Table 1. Pretreatment Characteristics Characteristics p53 available p53 not done P value Treatment RT+ 5-FU 24 (38%) 121 (49%) RT+ 5-FU+ MMC 40 (62%) 125 (51%) 0.13 Gender Male 21 (33%) 87 (35%) 0.81 Female 43 (67%) 159 (65%) KPS 60 0 6 (2%) 70 or 80 13 (20%) 49 (20%) 0.86 90 or 100 51 (80%) 191 (78%) Histologyaa Central review. Keratinizing squamous 11 (17%) 69 (28%) Nonkeratinizing Baseloid squamous 50 (78%) 166 (67%) 0.11 Other 2 (3%) 4 (2%) Unknown 1 (2%) 7 (3%) Tumor size (largest dimension) 60 61 60 Mean 65 60 Median RT: radiation therapy; 5-FU: 5-fluorouracil; MMC: mitomycin C; KPS: Karnofsky performance status; UICC: International Union Against Cancer. a Central review. The treatment arms and results of RTOG 87-04 have been published previously.8 Briefly, patients were randomized to pelvic radiotherapy (intended dose: 45–50.4 Gy) to the pelvis with a randomization to concurrent 5-FU or concurrent 5-FU and mitomycin C (MMC). Patients with a positive posttreatment biopsy received an additional 9 Gy with concurrent 5-fluorouracil (5-FU) and cisplatin. All patients gave their written informed consent to participate in the study. Immunohistochemistry Formalin fixed, paraffin embedded slides were obtained from the original diagnostic biopsies. Paraffin was removed by soaking the specimens in xylene, and graded alcohols were used to rehydrate the tissue. Endogenous peroxidase activity was quenched by incubation of specimens in 3% hydrogen peroxide in phosphate-buffered saline (PBS) for 30 minutes. Following rinsing in PBS, the slides were placed in plastic jars containing distilled water and heated at high power (setting 10) in a 1200 W microwave oven. When boiling was noted, the microwave setting was immediately reduced to setting 3 for 7–8 minutes. The slides were then cooled for 10–15 minutes in distilled water and transferred to PBS just prior to immunostaining. All slides were incubated for 30 minutes in nonimmune rabbit serum. The slides were then incubated for 60 minutes at room temperature in the polyclonal rabbit antibody CM-1 (1/100; Signet Labs, Dedham, MA). Following washing in PBS, incubations in animal specific biotinylated secondary antibody and ABC reagent were performed for 30 minutes at room temperature (ABC Kit, Vector, Burlingame, CA). The slides were then treated with diaminobenzidine tetrahydrochloride (DAB), the chromogenic substrate of peroxidase, and counterstained with Gill hematoxylin no. 3. Staining results were assessed jointly by two of the authors (S.R.B. and E.R.S.). The percentage of stained malignant cells (5%, 5–10%, and >10%) were recorded. The positive control for p53 was a case of carcinoma in situ of the buccal mucosa known to overexpress p53. PBS was used in place of the primary antibody on one side of slides, which contained two sections of tissue to serve as a negative control. The tumor was considered to overexpress p53 if greater than 5% of the malignant cells were stained. Endpoints The endpoints for the study were locoregional control, no evidence of disease (NED) survival, and overall survival. Patients with a positive biopsy following induction therapy were considered a locoregional failure on the day of biopsy. Biopsies were performed 4–6 weeks following the completion of chemoradiation. Patients with a negative biopsy were considered to have experienced locoregional failure on the day when a recurrence in either the primary site or the regional lymph node(s) was first reported. In the seven patients without postinduction biopsy, the clinical assessment of locoregional disease was used to determine failure. Time to locoregional control was measured from the induction biopsy to the occurrence of the first failure. For the seven patients without biopsy, time was measured from time of first clinical assessment postinduction. For the remaining patients, NED survival was measured from the induction biopsy until the first occurrence of locoregional failure as stated above, distant metastases, or death from any cause. If none of these events occurred, NED survival was measured to the last date of follow-up. Overall survival was measured from study entry until the date of death for any cause or last date of follow-up. Statistical Methods The analysis was performed with all the data received in Radiation Therapy Oncology Group (RTOG) Headquarters and processed as of October 16, 1996. This time period includes 2 additional years of follow-up since the initial treatment report.8 The median follow-up was 4.75 years (range, 0.07–8.35 years). If the analysis is restricted to patients with p53 determination, the median follow-up is 5.02 years (range, 0.10–8.27 years). The patient characteristics and treatment assignment for various patient subgroups were compared by the Pearson chi-square test with the Yates correction factor. All of the statistical comparisons were made with two-tailed tests. Local control, NED survival, and overall survival were estimated by the Kaplan–Meier method.14 The univariate and the multivariate analyses of these three endpoints were performed with the log rank test and the Cox proportional hazards model, respectively.15, 16 The variables examined in the model were p53 status ( 5% vs. > 5%), International Union Against Cancer stage (I and II vs. III), age (60 vs. > 60 years), Karnofsky performance score (90–100 vs. 90), and protocol treatment (radiotherapy and 5-FU versus radiotherapy and 5-FU/MMC, including t the pilot). The selection of variables was done in a forward stepwise manner using 0.10 as the significance level. The coefficient associated with each variable in the model was used to estimate the relative risk of failing when one of its categories was compared with the other. A ratio of 1 would indicate no difference between them. The bigger the difference from 1, the greater was the difference in the failure rates in the two subgroups. RESULTS This analysis included 64 of the 310 patients randomized to radiotherapy and 5-FU or radiotherapy, 5-FU, and MMC on RTOG 87-04. All data underwent central RTOG review. The difference in absolute survival was not different for those patients for whom p53 status was determined when compared with those in whom it was not (Fig. 1, P = 0.78). There were no significant differences between these two groups in terms of treatment assignment, gender, Karnofsky performance status (KPS), histology, tumor size, clinical T classification, clinical N classification, or age (Table 1). Figure 1Open in figure viewerPowerPoint Absolute survival of patients enrolled in RTOG 87-04 is shown according to p53 determination. Nuclear overexpression of the p53 protein was found in 31 (48%) of the 64 patients analyzed, whereas less than 5% of the nuclei were positive in 33 (52%). Table 2 lists the pretreatment characteristics according to p53 status. There were no significant differences between these two groups in terms of treatment assignment, gender, KPS, histology, tumor size, clinical T classification, clinical N classification, or age. Table 2. Pretreatment Characteristics According to p53 Staining Characteristics >5% ≤5% P value Treatment RT+ 5-FU 8 (26%) 16 (48%) RT+ 5-FU+ MMC 23 (74%) 17 (52%) 0.11 Gender Male 10 (32%) 11 (33%) 0.86 Female 21 (68%) 22 (67%) KPS 70 or 80 5 (16%) 8 (24%) 0.69 90 or 100 26 (84%) 25 (76%) Histologyaa Central review. Keratinizing 3 (10%) 8 (24%) Nonkeratinizing 26 (84%) 24 (73%) 0.19 Other 2 (6%) 0 (0%) Unknown 0 (0%) 1 (3%) Tumor size (greatest dimension) 60 20 (65%) 17 (52%) Mean 63 60 Median 65 63 RT: radiation therapy; 5-FU: 5-fluorouracil; MMC: mitomycin C; KPS: Karnofsky performance status; UICC: International Union Against Cancer. a Central review. The locoregional control by p53 status is shown in Figure 2A. Forty-eight percent of patients whose tumors overexpressed p53 experienced a locoregional failure compared with 27% of those whose tumors did not. This difference was not statistically significant (P = 0.14). Subgroup analysis by p53 status and treatment arm suggested that those patients whose tumors did not overexpress p53 protein and who were treated with both 5-FU and MMC had the best control, whereas patients who received 5-FU only and had tumors that overexpressed p53 most often experienced local relapse (Fig. 2B). Among the patients whose tumors overexpressed p53, those who were treated with 5-FU and MMC appeared to have a superior outcome compared with those who received 5-FU alone. With the 64 patients distributed into 4 groups, it is not surprising that they were not statistically different. Figure 2Open in figure viewerPowerPoint Local regional control is shown according to (A) p53 status and (B) p53 status and treatment arm. The results for NED and absolute survival are also presented in Figures 3A and 4A. Forty-eight percent of patients whose tumors overexpressed the p53 protein had some type of recurrence. The failure rate was 33% for patients whose tumors did not overexpress p53 protein (P = 0.28). Deaths were reported in 45% and 21% of patients whose tumors did or did not overexpress the p53 protein, respectively (P = 0.14). As in locoregional control, there was the suggestion that the combination of p53 status and treatment arm had an effect on outcome (Figs. 3B and 4B). However, these differences were not statistically significant. Figure 3Open in figure viewerPowerPoint No evidence of disease (NED) survival is shown according to (A) p53 status and (B) p53 status and treatment arm. Figure 4Open in figure viewerPowerPoint Absolute survival is shown according to (A) p53 status and (B) p53 status and treatment arm. Table 3 presents the results following stepwise multivariate regression analysis. The only pretreatment characteristic predictive of locoregional control was UICC stage (I or II vs. III, P = 0.0083). p53 status was not a significant predictor (P = 0.13). In terms of NED survival and absolute survival, UICC stage was again predictive (P = 0.0017 and 0.011, respectively). Differences in NED survival and absolute survival based on p53 status were not statistically significant (P = 0.27 and 0.14, respectively). Table 3. Stepwise Multivariate Regression Final Models 1. Local Regional Control (n = 64) Variable Parameter estimate Standard error Chi-square P value Risk ratio UICC stage 1.10 0.42 0.0083 3.02 p53 status 0.63 0.42 0.13 1.89 2. NED survival (n = 64) Variable Parameter estimate Standard error Chi-square P value Risk ratio UICC stage 0.97 0.41 0.0017 2.64 p53 status 0.44 0.40 0.27 1.55 3. Absolute survival (n = 64) Variable Parameter estimate Standard error Chi-square P value Risk ratio UICC stage 1.14 0.45 0.011 3.11 p53 status 0.68 0.46 0.14 1.98 UICC: International Union Against Cancer; NED: no evidence of disease. DISCUSSION RTOG 87-04 was a prospective trial in which patients with squamous cell carcinoma of the anal canal were randomized to receive definitive irradiation and 5-FU chemotherapy or irradiation and 5-FU plus MMC. This trial demonstrated that, despite greater toxicity, the 5-FU/MMC arm was significantly superior to the 5-FU alone arm, and thus justified its continued use.8 This retrospective review of material from RTOG 87-04 was undertaken to determine whether p53 mutation was of prognostic significance in this disease site. This study utilized immunohistochemically detected overexpression of the p53 protein as a surrogate for a more direct measurement of p53 mutation (such as single strand conformation polymorphism DNA analysis). Although the IHC methods we used did not differentiate between mutant and wt p53 proteins, it has previously been demonstrated that the mutant protein has a longer half-life and thus can more readily be detected.17, 18 Such an approach has been shown to be appropriate by many investigators. In an analysis of 78 head and neck carcinomas, Ahomadegbe et al. performed both direct analysis of p53 mutations and IHC.19 They found the correlation between p53 mutation and protein overexpression to be significant (P < 0.0001). Zheng et al. determined the p53 status of 52 patients with primary carcinoma of the fallopian tube by both IHC and polymerase chain reaction–single strand conformation polymorphism (PCR-SSCP).20 They found that IHC was 100% sensitive and 83.3% specific in detecting mutations in reference to PCR-SSCP. The prognostic significance of p53 status has been variable in a number of human malignancies. Nakopoulou et al. performed IHC analysis for the p53 protein on the transurethral biopsy specimens of 87 patients with superficial and invasive bladder carcinoma.21 Overexpression was noted in 48.3% of cases. Univariate analysis demonstrated a significantly inferior overall survival among the patients with invasive cancers whose tumors overexpressed p53. Although this association was lost on multivariate analysis, the combination of p53 overexpression and aneuploidy was strongly correlated with poor survival in the final model. Victorzon et al. performed IHC staining on 242 patients with gastric carcinoma to determine whether p53 status was prognostic.22 Thirty-nine percent of the tumors overexpressed p53, and this finding was associated with decreased survival in univariate analysis. However, because p53 overexpression was associated with more advanced disease, this finding lost significance in multivariate analysis (P = 0.08). Reports in which the significance of p53 mutations remained associated with inferior outcome in multivariate analysis include those by Zheng et al.20 for carcinoma of the fallopian tube. In a review of 52 cases of primary carcinoma of the fallopian tube, they noted no difference in outcome based on p53 status if all tumor had been removed. However, in a subgroup of 22 patients with residual tumor following surgery, multivariate analysis revealed a statistically significant survival decrement if p53 was overexpressed (P = 0.0009). Silvestri et al. analyzed the tumors from 256 patients with lymph node negative breast carcinoma.23 p53 overexpression was associated with inferior 6-year relapse free and overall survival (P ≤ 0.0001 and 0.0001, respectively). In fact, p53 status was more prognostic than both labeling index and estrogen receptor status in multivariate analysis. Starzynska et al. reported the results of 200 patients with gastric carcinoma. Among the 92 patients with advanced tumors who underwent potentially curative surgery, multivariate analysis revealed that p53 overexpression was more predictive of decreased overall and disease free survival than pathologic lymph node status or tumor depth.24 In summary, the data presented suggest that overexpression of the p53 protein may identify a subgroup of patients with epidermoid carcinoma of the anal canal with a relatively poor outcome following chemoradiation. Further, subgroup analysis by both p53 status and treatment arm suggests that more aggressive treatment (5-FU and MMC as opposed to 5-FU alone) may improve outcome for patients whose tumors overexpress p53 protein. Because the results presented in this report were not statistically significant, no definitive statements can be made regarding the prognostic significance of overexpression or mutation of p53 in anal carcinoma. Rather, they generate a hypothesis that will be addressed in the forthcoming Phase III RTOG trial (95-03). Information regarding tumor p53 status will be prospectively obtained in this trial. Acknowledgements The authors thank Inna Bleyman and Katherine Renner for technical assistance. REFERENCES 1 Flam MS, John M, Lovalvo LJ. Definitive nonsurgical therapy of epithelial malignancies of the anal canal: a report of 12 cases. Cancer 1983; 51: 1378– 87. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 2 Nigro ND, Seydel HG, Considine B. Combined preoperative radiation and chemotherapy for squamous cell carcinoma of the anal canal. Cancer 1983; 51: 1826– 9. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 3 Cummings B, Keane T, Thomas G, Harwood A, Rider W. Results and toxicity of the treatment of anal canal carcinoma by radiation therapy and chemotherapy. Cancer 1984; 54: 2062– 8. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 4 Leichman L, Nigro ND, Vaitkevicius V. Cancer of the anal canal: model for preoperative adjuvant combined modality therapy. Am J Med 1985; 78: 211– 6. CrossrefPubMedWeb of Science®Google Scholar 5 Zelnick RS, Haas PA, Ajlouni M, Szilagyi E, Fox TA. Results of abdominoperineal resections for failures after combination chemotherapy and radiation therapy for anal canal cancers. Dis Colon Rectum 1992; 35: 574– 8. CrossrefCASPubMedWeb of Science®Google Scholar 6 Cummings BJ, Keane TJ, O'Sullivan B, Wong CS, Catton CN. Epidermoid anal cancer: treatment by radiation alone or by radiation and 5-fluorouracil with and without mitomycin-C. Int J Radiat Oncol Biol Phys 1991; 21: 1115– 25. CrossrefCASPubMedWeb of Science®Google Scholar 7 Svensson C, Goldman S, Friberg B. Radiation treatment of epidermoid cancer of the anus. Int J Radiat Oncol Biol Phys 1993; 27: 67– 73. CrossrefCASPubMedWeb of Science®Google Scholar 8 Flam M, John M, Pajak TF, Petrelli N, Myerson R, Doggett S, et al. Role of mitomycin in combination with flourouracil and radiotherapy, and of salvage chemoradiation in the definitive nonsurgical treatment of epidermoid carcinoma of the anal canal: results of a phase III randomized intergroup study. J Clin Oncol 1996; 14: 2527– 39. CrossrefCASPubMedWeb of Science®Google Scholar 9 Beahrs OH, Henson DE, Hutter RVP, Myers MH. American Joint Committee on Cancer. Manual for staging of cancer. Philadelphia: J. B. Lippincott, 1988. Google Scholar 10 Harmer M. TNM classification of malignant tumors. 3rd edition. Geneva, Switzerland: International Union Against Cancer, 1978. Google Scholar 11 Levine AJ, Momand J, Finlay KA. The p53 tumor suppressor gene. Nature 1991; 351: 453– 6. CrossrefCASPubMedWeb of Science®Google Scholar 12 Eliyahu D, Raz A, Gruss P, Givol D, Oren M. Participation of p53 cellular tumor antigen in transformation of normal embryonic cells. Nature 1984; 312: 646– 9. CrossrefCASPubMedWeb of Science®Google Scholar 13 Finlay CA, Hinds PW, Levine AJ. The p53 proto-oncogene can act as a suppressor of transformation. Cell 1989; 57: 1083– 93. CrossrefCASPubMedWeb of Science®Google Scholar 14 Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J Am Stat Assoc 1958; 53: 457– 81. Wiley Online LibraryCASWeb of Science®Google Scholar 15 Cox DR. Regression models and life tables. J R Stat Soc B 1972; 34: 187– 229. Wiley Online LibraryGoogle Scholar 16 Mantel N. Evaluation of survival data and two new rank order statistics arising in its consideration. Cancer Chemother Rep 1966; 5: 163– 70. Google Scholar 17 Gannon JV, Greaves R, Iggo R, Lane DP. Activating mutations in p53 produce a common conformational effect: a monoclonal antibody specific for the mutant form. EMBO J 1990; 9: 1595– 1602. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 18 Lechner MS, Mack DH, Finicle AB, Crook T, Vousden KH, Laimins LA. Human papillomavirus E6 proteins bind p53 in vivo and abrogate p53-mediated repression of transcription. EMBO J 1992; 11: 3045– 52. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 19 Ahomadegbe J, Barrois M, Fogel S, Le Bihan ML, Douc-Rasy S, Duvillard P, et al. High incidence of p53 alterations (mutation, deletion, overexpression) in head and neck primary tumors and metastases; absence of correlation with clinical outcome. Frequent protein overexpression in normal epithelium and in early noninvasive lesions. Oncogene 1995; 10: 1217– 27. CASPubMedWeb of Science®Google Scholar 20 Zheng W, Sung C, Cao P, Zhang ZF, Cai R, Godwin TA, et al. Early occurrence and prognostic significance of p53 alteration in primary carcinoma of the fallopian tube. Gynecol Oncol 1997; 64: 38– 48. CrossrefCASPubMedWeb of Science®Google Scholar 21 Nakopoulou L, Constantinides C, Papandropoulos J, Theodoropoulos G, Tzonou A, Giannopoulos A, et al. Evaluation of overexpression of p53 tumor suppressor protein in superficial and invasive transitional cell bladder cancer: comparison with DNA ploidy. Urology 1995; 46: 334– 40. CrossrefCASPubMedWeb of Science®Google Scholar 22 Victorzon M, Nordling S, Haglund C, Lundin J, Roberts PJ. Expression of p53 protein as a prognostic factor in patients with gastric cancer. Eur J Cancer 1996; 32A: 215– 20. CrossrefPubMedWeb of Science®Google Scholar 23 Silvestrini R, Benini E, Daidone MG, Veneroni S, Boracchi P, Cappelletti V, et al. p53 as an independent marker in lymph node–negative breast cancer patients. J Natl Cancer Inst 1993; 85: 965– 70. CrossrefCASPubMedWeb of Science®Google Scholar 24 Starzynska T, Markiewski M, Domagala W, Marlicz K, Mietkiewski J, Roberts SA, et al. The clinical significance of p53 accumulation in gastric carcinoma. Cancer 1996; 77: 2005– 12. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar Citing Literature Volume85, Issue615 March 1999Pages 1226-1233 FiguresReferencesRelatedInformation
Referência(s)