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MCM2 Is an Independent Predictor of Survival in Patients With Non–Small-Cell Lung Cancer

2001; Lippincott Williams & Wilkins; Volume: 19; Issue: 22 Linguagem: Inglês

10.1200/jco.2001.19.22.4259

1527-7755

Nithya Ramnath, F.J. Barbado Hernández, Dongfeng Tan, Joel A. Huberman, Nachimuthu Natarajan, Amy Beck, Andrew Hyland, Иван Тодоров, John S. Brooks, Gerold Bepler,

Lung Cancer Treatments and Mutations

PURPOSE: Minichromosome maintenance protein 2 (MCM2) is a component of the prereplicative complex. It is essential for eukaryotic DNA replication and is only expressed in proliferating cells. The prognostic utility of MCM2 compared with Ki-67, another marker of proliferating cells, on survival of patients with non–small-cell lung cancer (NSCLC) was studied. PATIENTS AND METHODS: We examined the immunohistochemical expression of MCM2 and Ki-67 in primary pathologic tumor specimens from 221 NSCLC patients. For each marker, the fraction of tumor cells with positive staining was assessed as a percentage and categorized into four groups: 0% to 24%, 25% to 49%, 50% to 74%, and ≥ 75%. MCM2 and Ki-67 immunoreactivities were compared with each other, and associations with pathologic and clinical parameters predictive of survival were analyzed with the χ 2 test. Cox regression models were used to assess associations between MCM2 and Ki-67 and survival while controlling for confounders. RESULTS: Independent variables significantly associated with survival were tumor stage, performance status, and staining category. Patients with less than 25% MCM2 immunoreactivity had a longer median survival time than patients with ≥ 25% MCM2 immunoreactivity (46 v 31 months; P = .039) and a lower relative risk (RR) of death (RR, 0.55, 95% confidence interval, 0.34 to 0.88). There was no significant association between survival and Ki-67 expression. CONCLUSION: Immunostaining of tumor cells for MCM2 is an independent prognostic parameter of survival for patients with NSCLC. Interpretable results can be obtained on more than 96% of paraffin-embedded specimens, and approximately 35% will be in the favorable subgroup, with less than 25% positively stained tumor cells. Whether MCM2 is predictive of response to therapy needs to be studied.