Analysis of HER-2/neu amplification in endometrial carcinoma by chromogenic in situ hybridization. Correlation with fluorescence in situ hybridization, HER-2/neu, p53 and Ki-67 protein expression, and outcome.
Fluorescence in situ hybridization (FISH) is the most widely used technique to detect HER-2/neu gene amplification; however, it is only available in some institutions. In contrast, chromogenic in situ hybridization (CISH) can be evaluated by routine light microscopy. In endometrial carcinoma there are few data concerning HER-2/neu status and prognosis. Therefore, we determined HER-2/neu gene status by CISH using a digoxigenin-labelled probe on 60 formalin-fixed paraffin-embedded endometrial carcinomas. The data were compared with the immunohistochemistry of HER-2/neu (A0485, TAB250), p53, Ki-67, clinicopathological factors, and survival. By conventional light microscopy, HER-2/neu amplification (>/=6 copies >50% cancer cells) was detected in 14% (8/59) tumours, HER-2/neu overexpression (>10% cells moderate/strong complete membrane staining) in 22% (13/60) for A0485, and 18% (11/60) for TAB250, p53 (>10% +cells) in 61% (36/59), and Ki-67 (>50% +cells) in 50% (30/60). Discordant cases for CISH and immunohistochemistry, as well as all (2+) were further analysed by FISH (Vysis). Among 10 cases (2+) and not amplified by CISH, two showed low-level amplification by FISH. Significant correlation was found between amplification and protein overexpression (P</=0.001), and a trend with nonendometrioid type, higher grade, and older age. A better outcome (Kaplan-Meier) was observed for patients with nonamplified (1-5 copies per nucleus) or low-level (6-10 copies) amplification tumours, low Ki-67 expression, age <50 years, endometrioid type, low FIGO (International Federation of Obstetrics and Gynaecology) grade and stage, superficial myometrial infiltration, and no lymph-vascular invasion (P</=0.036), but only as a trend for HER-2/neu protein negative (P=0.13). Cox analysis revealed age, FIGO grade and stage, myometrial infiltration, and lymph-vascular invasion to be independent prognostic factors (P</=0.05), and a trend for HER-2/neu gene copy number (0.18). In endometrial carcinoma, HER-2/neu gene status can be readily assessed by CISH in routine clinical practice, and it gives more prognostic information than HER-2/neu by immunohistochemistry. FISH analysis in (2+) cases but negative by CISH may detect additional tumours with low-level amplification.
Peiró
G
G
Institute of Pathology, Klinikum Grosshadern, Ludwig-Maximilians University, Munich, München, Germany. peiro_glo@gva.es
Mayr
D
D
Hillemanns
P
P
Löhrs
U
U
Diebold
J
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016889:Endometrial Neoplasms / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence; D019394:Ki-67 Antigen / Q000378:metabolism; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D016159:Tumor Suppressor Protein p53