Comparison of HER2 expression between primary colorectal cancer and their corresponding metastases

• Published in: Cancer medicine (Malden, MA) MA), 2014-06, Vol.3 (3), p.674-680
• Main Authors: Lee, Won‐Suk, Park, Yeon Ho, Lee, Jung Nam, Baek, Jeong‐Heum, Lee, Tae‐Hoon, Ha, Seung Yeon
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Biomarkers, Tumor - genetics; Colon cancer; Colorectal Neoplasms - genetics; Colorectal Neoplasms - pathology; Female; Gene Amplification; Gene Expression Regulation, Neoplastic; HER2; Humans; In Situ Hybridization, Fluorescence; KRAS; Liver Neoplasms - genetics; Liver Neoplasms - pathology; Lung Neoplasms - genetics; Lung Neoplasms - pathology; Male; metastasis; Middle Aged; Original Research; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins p21(ras); ras Proteins - genetics; Receptor, ErbB-2 - biosynthesis; Receptor, ErbB-2 - genetics
• ISSN: 2045-7634; 2045-7634
• DOI: 10.1002/cam4.228

The aim of this study was to compare human epidermal growth factor 2 (HER2) status in primary colorectal cancer and paired liver or lung metastasis. Gene amplification of HER2 has been intensively evaluated in contemporary oncology, especially in breast and stomach cancer. The knowledge of HER2 status in primary and metastatic sites may be of potential value for therapeutic decision making in metastatic colon cancer. The HER2 status was assessed by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in 94 colorectal cancer with corresponding liver or lung metastases. HER2 amplification was present in 19 of the 188 (10.1%) of both primary and metastases combined. Four (4.6%) patients showed HER2 amplification in the metastasis and 10 (10.6%) patients showed HER2 amplification in the primary tumor. In 14 cases (14.8%), the HER2 status of the primary lesions was different from that of the associated metastases. The presence of HER2 overexpression in KRAS mutant colon cancer was found in 5.3%. No relationship was found between HER2 expression and KRAS status (P = 0.486). The evidence of HER2 positive metastatic lesion and primary colorectal cancer suggest that HER2 assessment might be considered in selected cases when this may help change the therapeutic decision. HER2 was overexpressed in colon tumors harboring KRAS mutations in 5.3% of cases. HER2‐directed target therapy may be beneficial in this subgroup of patients.