Altered Pattern of Major Histocompatibility Complex Expression in Renal Carcinoma
2003; Elsevier BV; Volume: 162; Issue: 2 Linguagem: Inglês
10.1016/s0002-9440(10)63844-8
ISSN1525-2191
AutoresEl Chérif Ibrahim, Yves Allory, Frédéric Commo, B Gattegno, P Callard, Pascale Paul,
Tópico(s)Renal and related cancers
ResumoRenal epithelial cancers represent a heterogeneous group of neoplasms arising from the malignant transformation of presumed diverse cell lineages. We recently demonstrated that tumor-specific up-regulation of human leukocyte antigen (HLA)-G, a nonclassical HLA class Ib molecule that might be involved in immune evasion by tumor cells, frequently occurs in conventional (clear cell) renal carcinoma. We here examined whether HLA-G activation is a common process affecting all types of renal epithelial tumors. We analyzed a series of 38 paraffin-embedded tumors including clear cell, papillary, chromophobe, collecting duct carcinoma, and oncocytoma. Seven of 12 (58%) clear cell tumors were positive by immunohistochemistry, whereas all of the other subtypes of renal carcinoma were negative for HLA-G expression. Developing or adult normal renal tissue were devoid of HLA-G expression. We also observed that ectopic expression of HLA class II antigens occurs more frequently in clear cell renal carcinoma than in other subtypes of renal tumors. Moreover, in contrast to the common observation of a down-regulation of major histocompatibility complex class Ia antigens reported in various tumors, the concomitant study of the same biopsies for classical HLA class Ia antigen expression revealed a general increase of HLA class Ia expression, regardless of histological subtypes. These results provide evidence for the heterogeneity of major histocompatibility complex expression patterns in renal carcinoma and support the hypothesis that specific mechanisms underlying the malignant transformation into clear cell renal carcinoma up-regulate expression of HLA-G and to a lesser extent HLA class II molecule expression. Considering the immunotolerant role of HLA-G toward the immune response, these mechanisms may thus provide renal cell carcinoma tumor cells with additional means to escape immune surveillance. Renal epithelial cancers represent a heterogeneous group of neoplasms arising from the malignant transformation of presumed diverse cell lineages. We recently demonstrated that tumor-specific up-regulation of human leukocyte antigen (HLA)-G, a nonclassical HLA class Ib molecule that might be involved in immune evasion by tumor cells, frequently occurs in conventional (clear cell) renal carcinoma. We here examined whether HLA-G activation is a common process affecting all types of renal epithelial tumors. We analyzed a series of 38 paraffin-embedded tumors including clear cell, papillary, chromophobe, collecting duct carcinoma, and oncocytoma. Seven of 12 (58%) clear cell tumors were positive by immunohistochemistry, whereas all of the other subtypes of renal carcinoma were negative for HLA-G expression. Developing or adult normal renal tissue were devoid of HLA-G expression. We also observed that ectopic expression of HLA class II antigens occurs more frequently in clear cell renal carcinoma than in other subtypes of renal tumors. Moreover, in contrast to the common observation of a down-regulation of major histocompatibility complex class Ia antigens reported in various tumors, the concomitant study of the same biopsies for classical HLA class Ia antigen expression revealed a general increase of HLA class Ia expression, regardless of histological subtypes. These results provide evidence for the heterogeneity of major histocompatibility complex expression patterns in renal carcinoma and support the hypothesis that specific mechanisms underlying the malignant transformation into clear cell renal carcinoma up-regulate expression of HLA-G and to a lesser extent HLA class II molecule expression. Considering the immunotolerant role of HLA-G toward the immune response, these mechanisms may thus provide renal cell carcinoma tumor cells with additional means to escape immune surveillance. Unlike the widely expressed classical human leukocyte antigen class Ia molecules (HLA class Ia), HLA-A, HLA-B, and HLA-C, the nonclassical HLA Ib molecule, HLA-G, exhibits a physiological expression mainly restricted to the placental tissues, thymic epithelial medulla, peripheral blood, and amniotic fluid.1Le Bouteiller P Blaschitz A The functionality of HLA-G is emerging.Immunol Rev. 1999; 167: 233-244Crossref PubMed Scopus (168) Google Scholar, 2Rebmann V Pfeiffer K Pässler M Ferrone S Maier S Weiss E Grosse-Wilde H Detection of soluble HLA-G molecules in plasma and amniotic fluid.Tissue Antigens. 1999; 53: 14-22Crossref PubMed Scopus (182) Google Scholar The expression of HLA-G molecules on extravillous cytotrophoblast, which lacks HLA-A and HLA-B antigen expression, has led to the concept that HLA-G might contribute to the maternal-fetal tolerance.3Kovats S Main EK Librach C Stubblebine M Fisher SJ DeMars R A class I antigen, HLA-G, expressed in human trophoblasts.Science. 1990; 248: 220-223Crossref PubMed Scopus (1240) Google Scholar This idea was further strengthened by in vitro evidence that HLA-G molecules interact with the inhibitory receptors p49/KIR2DL4/CD158d and ILT2/LIR1/CD85j found on natural killer (NK) and T cells, thus lowering the cytotoxic activity of these effector cells.4Navarro F Llano M Bellon T Colonna M Geraghty DE Lopez-Botet M The ILT2(LIR1) and CD94/NKG2A NK cell receptors respectively recognize HLA-G1 and HLA-E molecules co-expressed on target cells.Eur J Immunol. 1999; 29: 277-283Crossref PubMed Scopus (313) Google Scholar, 5Ponte M Cantoni C Biassoni R Tradori-Cappai A Bentivoglio G Vitale C Bertone S Moretta A Moretta L Mingari MC Inhibitory receptors sensing HLA-G1 molecules in pregnancy: decidua-associated natural killer cells express LIR-1 and CD94/NKG2A and acquire p49, an HLA-G1-specific receptor.Proc Natl Acad Sci USA. 1999; 96: 5674-5679Crossref PubMed Scopus (336) Google Scholar, 6Rajagopalan S Long EO A human histocompatibility leukocyte antigen (HLA)-G-specific receptor expressed on all natural killer cells.J Exp Med. 1999; 189: 1093-1100Crossref PubMed Scopus (630) Google Scholar, 7Vitale M Castriconi R Parolini S Pende D Hsu M-L Moretta L Cosman D Moretta A The leucocyte Ig-like receptor (LIR)-1 for the cytomegalovirus UL18 protein displays a broad specificity for different HLA class I alleles: analysis of LIR-1+ NK cell clones.Int Immunol. 1999; 11: 29-35Crossref PubMed Scopus (100) Google Scholar, 8Saverino D Fabbi M Ghiotto F Merlo A Bruno S Zarcone D Tenca C Tiso M Santoro G Anastasi G Cosman D Grossi CE Ciccone E The CD85/LIR-1/ILT2 inhibitory receptor is expressed by all human T lymphocytes and down-regulates their functions.J Immunol. 2000; 165: 3742-3755PubMed Google Scholar, 9Riteau B Menier C Khalil-Daher I Martinozzi S Pla M Dausset J Carosella ED Rouas-Freiss N HLA-G1 co-expression boosts the HLA class I-mediated NK lysis inhibition.Int Immunol. 2001; 13: 193-201Crossref PubMed Scopus (135) Google Scholar In addition, HLA-G may modulate antigen presentation by other immune effector cells by interacting with inhibitory receptors such as ILT2/LIR1/CD85j and ILT4/CD85d, expressed on B lymphocytes, monocytes, and dendritic cells.10Colonna M Navarro F Bellon T Llano M Garcià P Samaridis J Angman L Cella M Lopez-Botet M A common inhibitory receptor for major histocompatibility complex class I molecules on human lymphoid and myelomonocytic cells.J Exp Med. 1997; 186: 1809-1818Crossref PubMed Scopus (800) Google Scholar, 11Colonna M Samaridis J Cella M Angman L Allen RL O'Callaghan CA Dunbar R Ogg GS Cerundolo V Rolink A Human myelomonocytic cells express an inhibitory receptor for classical and nonclassical MHC class I molecules.J Immunol. 1998; 160: 3096-3100PubMed Google Scholar, 12Allan DS Colonna M Lanier LL Churakova TD Abrams JS Ellis SA McMichael AJ Braud VM Tetrameric complexes of human histocompatibility leukocyte antigen (HLA-G) bind to peripheral blood myelomonocytic cells.J Exp Med. 1999; 189: 1149-1156Crossref PubMed Scopus (214) Google Scholar Moreover, HLA-G leader peptides can favor cell surface expression of another HLA class Ib molecule, HLA-E, which is the specific ligand of both triggering and inhibitory CD94/NKG2 heterodimeric receptor expressed by all NK cells and subsets of T cells.13Llano M Lee N Navarro F Garcia P Pablo Albar J Geraghty DE Lopez-Botet M HLA-E-bound peptides influence recognition by inhibitory and triggering CD94/NKG2 receptors: preferential response to an HLA-G-derived nonamer.Eur J Immunol. 1998; 28: 2854-2863Crossref PubMed Scopus (326) Google Scholar, 14Valés-Gomez M Reyburn HT Erskine RA Lopez-Botet M Strominger JL Kinetics and peptide dependency of the binding of the inhibitory NK receptor CD94/NKG2-A and the activating receptor CD94/NKG2-C to HLA-E.EMBO J. 1999; 18: 4250-4260Crossref PubMed Scopus (306) Google Scholar Alteration of HLA class Ia and II antigen expression frequently occurs in cancer and is considered to favor tumor escape from immune surveillance.15Marincola FM Jaffee EM Hicklin DJ Ferrone S Escape of human solid tumours from T-cell recognition: molecular mechanisms and functional significance.Adv Immunol. 2000; 74: 181-263Crossref PubMed Google Scholar Recently, we and others have detected HLA-G molecules ex vivo in a variety of malignancies in which down-regulation of HLA class Ia antigens is also commonly reported, including melanoma, breast, and lung cancers and cutaneous lymphoma.16Paul P Adrian-Cabestre F Le Gal FA Khalil-Daher I Le Danff C Schmid M Mercier S Avril MF Dausset J Guillet J-G Carosella ED Heterogeneity of HLA-G gene transcription and protein expression in malignant melanoma biopsies.Cancer Res. 1999; 59: 1954-1960PubMed Google Scholar, 17Wagner SN Rebmann V Willers CP Grosse-Wilde H Goos M Expression analysis of classic and non-classic HLA molecules before interferon alfa-2b treatment of melanoma.Lancet. 2000; 356: 220-221Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar, 18Urosevic M Kurrer MO Kamarashev J Mueller B Weder W Burg G Stahel RA Dummer R Trojan A Human leukocyte antigen up-regulation in lung cancer associates with high-grade histology, human leukocyte antigen class I loss and interleukin-10 production.Am J Pathol. 2001; 159: 817-824Abstract Full Text Full Text PDF PubMed Scopus (182) Google Scholar, 19Urosevic M Willers J Mueller B Kempf W Burg G Dummer R HLA-G protein up-regulation in primary cutaneous lymphoma is associated with interleukin-10 expression in large cell T-cell lymphomas and indolent B-cell lymphomas.Blood. 2002; 99: 609-617Crossref PubMed Scopus (151) Google Scholar, 20Lefebvre S Antoine M Uzan S McMaster M Dausset J Carosella ED Paul P Specific activation of the non-classical class I histocompatibility HLA-G antigen and expression of the ILT2 inhibitory receptor in human breast cancer.J Pathol. 2002; 196: 266-274Crossref PubMed Scopus (154) Google Scholar We have previously reported that HLA-G expression in renal cell carcinomas (RCCs) was exclusively restricted to tumor cells.21Ibrahim EC Guerra N Terrier Lacombe M-J Angevin E Chouaib S Carosella ED Caignard A Paul P Tumor-specific up-regulation of the nonclassical class I HLA-G antigen expression in renal carcinoma.Cancer Res. 2001; 61: 6838-6845PubMed Google Scholar Constitutive and interferon-inducible cell surface expression of HLA-G proteins was also demonstrated in vitro on primary cultured thymic or amniotic epithelial cells22Lefebvre S Berrih-Aknin S Adrian F Moreau P Poea S Gourand L Dausset J Carosella ED Paul P A specific ISRE of the distal HLA-G promoter binds IRF-1 and mediates enhancement of this nonclassical histocompatibility class I gene by IFN-beta.J Biol Chem. 2001; 276: 6133-6139Crossref PubMed Scopus (97) Google Scholar and on a renal carcinoma cell line derived from an HLA-G-positive tumor biopsy.21Ibrahim EC Guerra N Terrier Lacombe M-J Angevin E Chouaib S Carosella ED Caignard A Paul P Tumor-specific up-regulation of the nonclassical class I HLA-G antigen expression in renal carcinoma.Cancer Res. 2001; 61: 6838-6845PubMed Google Scholar Collectively, these results suggest that HLA-G molecule expression might be involved in the impairment of the anti-tumor immunity or resistance to immunotherapeutic approaches such as interferon-α. Adult RCCs consist of a heterogeneous group of tumors with distinct clinical, histopathological, and genetic features.23Kovacs G Akhtar M Beckwith BJ Bugert P Cooper CS Delahunt B Eble JN Fleming S Ljunberg B Medeiros LJ Moch H Reuter VE Ritz E Roos G Schmidt D Srigley JR Storkel S van den Berg E Zbar B The Heidelberg classification of renal cell tumours.J Pathol. 1997; 183: 131-133Crossref PubMed Scopus (1180) Google Scholar, 24Storkel S Eble JN Adlakha K Amin M Blute ML Bostwick DG Darson M Delahunt B Iczkowski K Classification of renal cell carcinoma: Workgroup No. 1. Union Internationale Contre le Cancer (UICC) and the American Joint Committee on Cancer (AJCC).Cancer. 1997; 80: 987-989Crossref PubMed Scopus (812) Google Scholar, 25Reuter VE Presti Jr, JC Contemporary approach to the classification of renal epithelial tumors.Semin Oncol. 2000; 27: 124-137PubMed Google Scholar In our initial survey, most renal carcinomas analyzed were of the conventional (clear cell) type of renal carcinoma.21Ibrahim EC Guerra N Terrier Lacombe M-J Angevin E Chouaib S Carosella ED Caignard A Paul P Tumor-specific up-regulation of the nonclassical class I HLA-G antigen expression in renal carcinoma.Cancer Res. 2001; 61: 6838-6845PubMed Google Scholar Therefore, the present study aimed at determining if HLA-G, as well as other HLA class Ia and II molecules, exhibit specific patterns of expression in the most common morphotypes of renal epithelial neoplasms. We therefore performed immunochemistry analysis of major histocompatibility complex (MHC) antigen expression in a series of paraffin-embedded lesions including conventional (clear cell) (accounting for ∼75 to 80% of all RCCs), papillary (∼10 to 15%), and chromophobe (∼5%) RCC, collecting duct carcinoma (<1%), and oncocytoma (which are considered as benign renal neoplasms).23Kovacs G Akhtar M Beckwith BJ Bugert P Cooper CS Delahunt B Eble JN Fleming S Ljunberg B Medeiros LJ Moch H Reuter VE Ritz E Roos G Schmidt D Srigley JR Storkel S van den Berg E Zbar B The Heidelberg classification of renal cell tumours.J Pathol. 1997; 183: 131-133Crossref PubMed Scopus (1180) Google Scholar Furthermore, as HLA molecule expression within the tumors could be related to the histogenesis and/or reflect activation of oncofetal or embryonic genes, we investigated physiological HLA antigen expression in developing and adult normal renal tissue. We here report that HLA-G expression is strictly restricted to the clear cell-type RCCs, whereas global HLA class Ia expression appears up-regulated in most renal tumors regardless of their histological subtype. Tumor and adjacent normal renal samples were obtained from 38 patients who had undergone radical nephrectomy (Tenon Hospital, Paris, France). None of these cases belonged to the previous published study.21Ibrahim EC Guerra N Terrier Lacombe M-J Angevin E Chouaib S Carosella ED Caignard A Paul P Tumor-specific up-regulation of the nonclassical class I HLA-G antigen expression in renal carcinoma.Cancer Res. 2001; 61: 6838-6845PubMed Google Scholar None of the patients had received preoperative therapy. Embryonic and fetal kidneys were retrieved from therapeutic abortion material conserved in the archives of the Department of Pathology (Tenon Hospital, Paris, France); a microscopic examination confirmed that renal tissue was morphologically normal. All tissues were cut at 4 μm thickness, and mounted on precleaned glass microscope slides (Menzel-Gläser, Braunsheig, Germany). Renal cell tumors were identified as conventional (clear cell) (ccRCC, n = 12), papillary carcinoma (pRCC, n = 10), chromophobe (chRCC, n = 7) RCC, collecting duct carcinoma (Bellini, n = 4), or renal oncocytoma (n = 5) according to the revised classification of renal tumors.23Kovacs G Akhtar M Beckwith BJ Bugert P Cooper CS Delahunt B Eble JN Fleming S Ljunberg B Medeiros LJ Moch H Reuter VE Ritz E Roos G Schmidt D Srigley JR Storkel S van den Berg E Zbar B The Heidelberg classification of renal cell tumours.J Pathol. 1997; 183: 131-133Crossref PubMed Scopus (1180) Google Scholar, 24Storkel S Eble JN Adlakha K Amin M Blute ML Bostwick DG Darson M Delahunt B Iczkowski K Classification of renal cell carcinoma: Workgroup No. 1. Union Internationale Contre le Cancer (UICC) and the American Joint Committee on Cancer (AJCC).Cancer. 1997; 80: 987-989Crossref PubMed Scopus (812) Google Scholar Tumors were staged according to tumor-node-metastasis (TNM) classification and examined for nuclear grade (I to IV according to Fuhrman classification).26Sobin LH Witteking CH International Union Against Cancer.TNM Classification of Malignant Tumors. ed 5. Wiley-Liss, New York1997Google Scholar, 27Fuhrman SA Lasky LC Limas C Prognostic significance of morphologic parameters in renal cell carcinoma.Am J Surg Pathol. 1982; 6: 655-663Crossref PubMed Scopus (2370) Google Scholar The primary monoclonal antibodies (mAbs) used in this study were the anti-leukocyte common antigen/CD45RB (clone PD7/26, 1:100 dilution; DAKO, Glostrup, Denmark); the anti-HLA-DP, anti-HLA-DR, and anti-HLA-DQ antigens (clone CR3/43, 1:50 dilution; DAKO, Denmark); the anti-gp100/Pmel17 (clone HMB45, 1/50 dilution; DAKO, Carpinteria, CA); 4H84, an IgG1 (1:500 dilution of ascitic fluid) anti-native and denatured HLA-G heavy chain28McMaster M Zhou Y Shorter S Kapasi K Geraghty D Lim K-H Fisher S HLA-G isoforms produced by placental cytotrophoblasts and found in amniotic fluid are due to unusual glycosylation.J Immunol. 1998; 160: 5922-5928PubMed Google Scholar kindly provided by M. McMaster (University of California, San Francisco, CA); HC-10, an anti-determinant preferentially expressed on β2m-free most HLA-B and HLA-C and some HLA-alleles of HLA class Ia heavy chains29Stam NJ Spits H Ploegh HL Monoclonal antibodies raised against denatured HLA-B locus heavy chains permit biochemical characterization of certain HLA-C locus products.J Immunol. 1986; 137: 2299-2306PubMed Google Scholar kindly provided by H. L. Ploegh (Harvard Medical School, Boston, MA). The NCAM-L1 (clone C-20, 1:150 dilution), a goat polyclonal antibody raised against a peptide mapping to the carboxy terminus of human anti-L1-CAM (Santa Cruz Biotechnology, Santa Cruz, CA) was used in double-staining experiments. Immunostainings using mouse mAbs as a first antibody were conducted as previously described.21Ibrahim EC Guerra N Terrier Lacombe M-J Angevin E Chouaib S Carosella ED Caignard A Paul P Tumor-specific up-regulation of the nonclassical class I HLA-G antigen expression in renal carcinoma.Cancer Res. 2001; 61: 6838-6845PubMed Google Scholar Negative controls of immunostaining procedures were obtained by using the HMB45 mAb as a primary antibody. For double staining with anti-L1-CAM antibody and HC-10, deparaffinized slides were incubated for 30 minutes with the NCAM-L1 antibody diluted in Tris-buffered saline (pH 7.5) with 0.1% Tween-20, 3% albumin, and 10% rabbit normal serum (DAKO), followed by sequential incubations with rabbit anti-goat biotinylated antibody (1:400 dilution, DAKO) and alkaline phosphatase-conjugated streptavidin (1:250 dilution, DAKO). The immunoreaction was visualized with developing solutions containing blue-purple 5-bromo-4-chloro-3-indoxyl phosphate with nitro-blue-tetrazolium-chloride (BCIP/NBT) supplemented with 1 mmol/L of levamisole (to quench endogenous alkaline phosphatase activity). To block antibody cross reactivity and retrieve epitopes, the slides were microwaved twice for 5 minutes at 360 W.30Lan HY Mu W Nikolic-Paterson DJ Atkins RC A novel, simple, reliable, and sensitive method for multiple immunoenzyme staining: use of microwave oven heating to block antibody crossreactivity and retrieve antigens.J Histochem Cytochem. 1995; 43: 97-102Crossref PubMed Scopus (349) Google Scholar The sections were then processed on an automated instrument (Ventana Nexes; Ventana Medical Systems, Paris, France) for the HC-10 immunostaining (1:1000 dilution) using an indirect biotin avidin system, the Ventana Basic DAB detection kit (Ventana Medical Systems) according to the manufacturer's instructions. Finally, sections were dehydrated and mounted in Eukitt. HLA class Ia, class Ib (HLA-G), and class II expression was compared between the groups classified according to the histological subtype, the TNM stage, or the nuclear grade, using chi-square test and the Fisher's exact t-tests. Immunohistochemical analysis of a series of 38 renal carcinoma and adjacent healthy tissues revealed that HLA-G protein expression was exclusively detected in tumor cells, both with a membrane and to a less extent a cytoplasmic staining. Of note, all CD45RB-positive inflammatory cells were negative for HLA-G expression (data not shown). Moreover, HLA-G protein expression was found in the clear cell subtype of carcinoma but never detected in papillary RCC, chromophobe RCC, collecting duct carcinoma, and oncocytoma (Figure 1A and Figure 2). This selective activation of HLA-G antigen expression occurred in 7 of 12 cases (58.3%) independent of the age and gender of patients as well as the nuclear grade and the size of tumors (Table 1).Figure 2Rate of HLA-G, HLA-B, and HLA-C and HLA II antigen immunodetection in tumor cells in a series of paraffin-embedded renal carcinomas corresponding to clear cell (ml), papillary (p), chromophobe (ch), collecting duct (B), and oncocytoma (o) subtypes. Statistical significance of the differential expression in one subtype of carcinoma as compared to the other type of tumors is indicated above the histograms.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Table 1Comparative Immunohistochemical Analysis of HLA-G, HLA-Class Ia and HLA Class II Molecule Expression in a Series of Renal CarcinomasPatient no.Age/sexHistologyTNM classificationNuclear grade*According to Fuhrman classification.HLA-GHLA-B and -C†Immunoreactivity confined to epithelial tubular or tumoral cells is reported.HLA-DP, -DQ, -DR†Immunoreactivity confined to epithelial tubular or tumoral cells is reported.165/MHK−‡Scoring of immunohistochemical staining was performed as follows: −, no reactivity; +/−, staining confined to 90% of cells were immunoreactive.+/−−ccRCCT2II++++−276/FHK−+/−−ccRCCT1II−+++−354/MHK−+/−−ccRCCT2II+++++/−469/MHK−+/−+/−ccRCCT1III+++++−556/MHK+/−−ccRCCT1III+++++++/−677/MHK−+/−+/−ccRCCT1III+++++754/FHK−+/−−ccRCCT2III+++++/−858/MHK−+/−−ccRCCT3bIII−++/−948/MHK−++−ccRCCT3bIII−+++++1068/MHK−+++/−ccRCCT3bIV−++++1151/MHK−++/−ccRCCT3IV+++++++++1257/MHK−−−ccRCCT3bIV−++−1333/MHK−+/−−pRCCT1II−+++−1456/MHK−++/−pRCCT1III−+++−1555/MHK−+/−−pRCCT2III−+++−1673/MHK−+/−+/−pRCCT1III−+−1753/MHK−+++pRCCT1III−++++1856/MHK−+++−pRCCT1III−+++−1938/MHK−++/−pRCCT2IV−++++2048/MHK−+/−+/−pRCCT2III−+++−2165/MHK−+/−−pRCCT1II−+++−22§Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined.51/FpRCCT1IV−+−2363/MHK−+/−−chRCCT1II−+/−−2434/MHK−+/−−chRCCT2II−+/−−2553/FHK−+/−+/−chRCCT3aIV−++++26§Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined.62/FchRCCT3aIV−+/−++27§Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined.NAchRCCT3III−+/−+/−28§Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined.NAchRCCT3III−+++−29§Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined.NAchRCCT3III−+−30NAHK−−−BelliniT3IV−++/−31NAHK−+/−−BelliniT3IV−+−32§Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined.NABelliniT3IV−++++++33§Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined.NABelliniT3IV−+++−3484/MHK−+/−−Oncocytoma−+−3562/MHK−+/−+/−Oncocytoma−+++−3665/MHK−+/−+Oncocytoma−+++−3767/FHK−−−Oncocytoma−+++−3853/FHK−+−Oncocytoma−+++/−* According to Fuhrman classification.† Immunoreactivity confined to epithelial tubular or tumoral cells is reported.‡ Scoring of immunohistochemical staining was performed as follows: −, no reactivity; +/−, staining confined to 90% of cells were immunoreactive.§ Healthy kidney was not available for analysis. NA: not available, HK: healthy kidney, ccRCC: clear cell renal carcinoma, pRCC: papillary renal carcinoma, chRCC: chromophobe renal carcinoma, ND: not determined. Open table in a new tab Concomitant with HLA-G expression analysis, serial tissue sections were stained for HLA class Ia and II expression (Table 1). More pronounced anti-HLA class Ia staining was always observed in tumor cells, as compared with normal adjacent tubule cells. This unexpected HLA class Ia expression pattern was detected in all subtypes of renal carcinoma analyzed, with the exception of chromophobe carcinoma (Table 1 and Figure 2). In addition, total HLA class Ia antigen loss, frequently reported in various types of tumors, was never observed in our series. HLA class II immunoreactivity could be observed in tumor cells in each histological group of renal carcinoma. Nevertheless, HLA class II-induced expression in tumor cells was significantly more frequent in clear cell renal carcinoma (Figure 1, Figure 2) . HLA-G expression was undetectable in the normal renal tissue adjacent to the tumor, in particular in the proximal tubules from which clear cell RCC is supposed to originate. Of interest, the detailed analysis of HC-10 mAb reactivity on normal kidney tissues revealed a heterogeneous pattern of staining. Mesangial and endothelial cell membranes were intensely stained for HLA-B and HLA-C antigen expression, whereas the immunostaining was cytoplasmic in tubules, often very low or negative in proximal convoluted tubules, slightly increased in distal tubular cells, and moderate to high in some cells of connecting tubules and the collecting duct. In these latter structures, we observed an alternation of HLA Ia-positive and -negative antigen expression, which is reminiscent of the alternation pattern of intercalated and principal cells described in these segments.31Helbert MJF Dauwe SEH De Broe ME Flow cytometric immunodissection of the human distal tubule and cortical collecting duct system.Kidney Int. 2001; 59: 554-564Crossref PubMed Scopus (30) Google Scholar The double staining of normal adult kidney tissues with HC-10 mAb and an anti-L1-CAM polyclonal antibody that is specific to an adhesion molecule basolaterally expressed only by principal cells,31Helbert MJF Dauwe SEH De Broe ME Flow cytometric immunodissection of the human distal tubule and cortical collecting duct system.Kidney Int. 2001; 59: 554-564Crossref PubMed Scopus (30) Google Scholar, 32Debiec H Christensen EI Ronco PM The cell adhesion molecule L1 is developmentally regulated in the renal epithelium and is involved in kidney branching morphogenesis.J Cell Biol. 1998; 143: 2067-2079Crossref PubMed Scopus (88) Google Scholar showed that expression of HLA class Ia antigens and L1-CAM molecules is mutually exclusive, L1-CAM-negative cells being stained for HLA class Ia antigens and corresponding to intercalated cells (Figure 1B). HLA class II expression was mainly observed in mesangial and endothelial cell membranes of glomeruli and juxtatubular capillaries within normal kidney tissues, and weakly in rare dispersed tubular cell cytoplasms, in proximal, distal, and connecting tubules and in collecting ducts. To explore HLA antigen expression during embryonic and fetal kidney morphogenesis, biopsies from developing kidneys at different ages were analyzed by immunohistochemistry (8, 10, 17, 18, 25, and 27 weeks of gestation). HLA-G molecules were never detected in developing kidney whereas HLA-B and HLA-C antigens were expressed as early as 8 weeks within endothelial cells, and appeared in epithelial segments by 17 weeks. As observed in adult kidney, HLA class Ia antigen expression is restricted to a minority of collecting duct cells (Figure 1C). At this stage of development (17 to 18 weeks of gestation) the differentiation between principal versus intercalated cells is not achieved. Nevertheless HC-10-positive cells possess a smaller cytoplasm than the HC-10-negative cells within which they seem to intercalate (Figure 1C, right enlargement). HLA class II antigens were almost exclusively expressed by endothelial cells but not by epithelial cells in the developing kidney. Adult RCC is a challenging model for understanding the mechanisms involved in tumor escape from immune surveillance. In a previous study, we reported that clear cell RCC displayed an ectopic HLA-G expression pattern, which suggested
Referência(s)