c-erbB-2 is not a major factor in the development of colorectal cancer

We have investigated c- erb B-2 protein expression in a large cohort of well-characterized colorectal tumours, and in a subset of lymph node metastases. We have also evaluated a Val 655 Ile single nucleotide polymorphism, which is associated with an increased risk of breast cancer, in a subset of the colorectal cancer patients and in healthy control subjects. Immunohistochemical studies revealed that while 81.8% of tumours expressed c- erb B-2, in the majority of cases equivalent levels of c- erb -B2 were seen in adjacent normal mucosa. Colon tumours were significantly more likely to express c- erb B-2 than rectal tumours ( P =0.015). Only 52.4% of the metastases displayed staining patterns concordant with their primary tumour, indicating that determination of c- erb B-2 protein in colorectal tumours cannot predict the status of lymph node metastases. PCR–RFLP analysis of the Val 655 Ile single nucleotide polymorphism demonstrated that allele frequencies were identical between colorectal cancer patients and a control group of Caucasian subjects (Ile=0.80 and Val=0.20 in each case), indicating that it is not related to the risk of developing colorectal cancer in this population. Furthermore, there was no relationship between c- erb B-2 protein expression and gene polymorphism ( P =0.58). In terms of prognosis, no association was seen between either c- erb B-2 protein expression or the presence of the Val allele and patient survival ( P >0.05 in each case), suggesting that c- erb B-2 is not a prognostic marker in colorectal cancer.