Amplification of c-myc Oncogene by Chromogenic and Fluorescence In Situ Hybridization in Archival Breast Cancer Tissue Array Samples

Abstract

SUMMARY:Fluorescence in situ hybridization (FISH) is currently considered to be the most specific and sensitive method for detection of oncogene amplifications in human tumor samples. However, FISH requires fluorescence microscopy, which is tedious and does not allow histopathologic evaluation of the cells and tissues examined. Here we compared FISH with the newly developed chromogenic in situ hybridization (CISH), which uses peroxidase enzyme for probe detection instead of fluorescent dyes. CISH was found to be highly concordant with FISH in a tissue array series of 177 archival breast cancer samples. This was true both when comparing CISH with single-color and two-color FISH, the latter including the chromosome 8 centromere probe as reference (the kappa coefficients were 0.67 and 0.76, respectively). Clinicopathologic correlations of c-myc amplification as detected by FISH and CISH were generally the same. By both methods, c-myc amplification was significantly associated with high histologic grade, negative progesterone receptor status, DNA aneuploidy, and high S-phase fraction. c-myc amplification was strongly associated with poor distant metastasis-free survival when amplification was detected by CISH (p ϭ 0.0013), but this association was weaker when FISH was used (p ϭ 0.16 for two-color FISH and p ϭ 0.065 for single-color FISH). These data suggest that CISH is at least as sensitive and specific as FISH in the detection of oncogene amplification in human tumor samples. The possibility for concomitant tissue architecture evaluation using an ordinary transmitted light microscope may favor the use of CISH over FISH in oncogene amplification detection in large tumor series, and tissue arrays and, ultimately, in routine clinical diagnostics. (Lab Invest 2001, 81:1545-1551.

Comparison of genomic abnormalities between BRCAX and sporadic breast cancers studied by comparative genomic hybridization

“…Previous reports have correlated gain of 8q with higher tumour grade, tumour aggressiveness, positive lymph node metastasis and involvement of c-myc oncogene. 26 The sporadic breast cancers studied here showed similar correlations, however, we have not observed this phenomenon in the group of BRCAX tumours that showed 8q gains more frequently in Grade II breast cancers and only a slightly higher incidence of this aberration in tumours with positive lymph nodes. These discrepancies may be due to the relatively small number of tumours analysed here (8 of Grade II vs. 7 of Grade III), however in BRCAX group 8q-qains were the most frequently observed abnormality (83%), which is also significantly more frequent than that observed by other authors in different tumour types (Table III).…”

Reliability of Tissue Microarrays in Detecting Protein Expression and Gene Amplification in Breast Cancer

“…The FISH technique has been successfully used for analysis of gene amplification by high throughput tissue microarray (16,18,24,25). To validate the FISH analysis in our tissue microarray, we performed HER-2/neu gene amplification analysis and compared the data obtained with the original full-section FISH data.…”

HER2 expression in breast cancer primary tumours and corresponding metastases. Original data and literature review

“…The CISH analysis was carried out according to the description by Rummukainen et al (2001). Briefly, before hybridisation, the tissue sections were deparaffinised, washed and dried.…”