EXPRESSION OF C-MET IS A STRONG INDEPENDENT PROGNOSTIC FACTOR IN BREAST-CARCINOMA

BACKGROUND. The c-met protooncogene encodes the met protein, the recep tor for scatter factor/hepatocyte growth factor, a growth factor that modulates the motility and stable interaction of the epithelial cells. This study assesses the expression of met receptor in breast carcinom a and its prognostic value with respect to survival. METHODS, Immunofl uorescence was used to evaluate 91 archival breast carcinoma specimens using a polyclonal antibody to the cytoplasmic domain of the receptor . Cases were scored by two pathologists on a percentage basis and then converted to binary scores (positive or negative) on the basis of a b imodal distribution. RESULTS, Strong expression of met was found in 20 invasive ductal breast tumor specimens (22%). The 5-year survival of patients whose tumors showed decreased met expression was 89%, in cont rast to a 52% 5-year survival rate in patients whose tumors expressed met (P = 0.008). This trend also was observed in patients without lymp h node metastases at presentation, in whom met negative patients had a 95% 5-year survival compared with only 62% for met positive patients (P = 0.006) Multivariate analysis using the Cox proportional hazards m odel showed met expression to be an independent predictor of survival, with a predictive value nearly equivalent to that associated with lym ph node status. CONCLUSIONS. The authors conclude that expression of m et in patients with invasive ductal carcinoma of the breast is a stron g, independent predictor of decreased survival and may be a useful pro gnostic marker with which to identify a subset of patients with more a ggressive disease. (C) 1998 American Cancer Society.