1. ¹Department of Medicine and Therapeutics, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2Z, UK
2. ²Department of Pathology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK

Correspondence: Dr HL McLeod, Washington University School of Medicine, Department of Medicine, Room 1021, CSRB NT, 660 South Euclid Avenue, Campus Box 8069, St. Louis, MO 63110-1093, USA. E-mail: hmcleod@im.wustl.edu

Received 12 July 2001; Revised 29 November 2001; Accepted 5 December 2001.

Abstract

We have investigated c-erbB-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 Val⁶⁵⁵Ile 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-erbB-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-erbB-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-erbB-2 protein in colorectal tumours cannot predict the status of lymph node metastases. PCR–RFLP analysis of the Val⁶⁵⁵Ile 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-erbB-2 protein expression and gene polymorphism (P=0.58). In terms of prognosis, no association was seen between either c-erbB-2 protein expression or the presence of the Val allele and patient survival (P>0.05 in each case), suggesting that c-erbB-2 is not a prognostic marker in colorectal cancer.