EXPRESSION OF INSULIN-LIKE GROWTH-FACTOR-I (IGF-I) IN FEMALE BREAST-CANCER AS RELATED TO ESTABLISHED PROGNOSTIC FACTORS AND LONG-TERM PROGNOSIS

The expression of insulin-like growth factor I (IGF-I) was analysed im munohistochemically in a series of 211 breast cancers with special emp hasis on its relationship to conventional prognostic factors and long- term prognosis. Altogether, IGF-I was expressed by the tumour cells in 91% of the breast carcinomas, and by stromal cells in 29%. The expres sion of IGF-I in cancer cells was weakly related to a high proportion of intraductal growth (P = 0.032), distinct tumour margins (P = 0.048) and high S-phase fraction (P = 0.074). In a univariate analysis, IGF- I expression in cancer cells was significantly related to a high survi val probability in the entire cohort (P = 0.0144) as well as in the ax illary lymph node positive tumours (P = 0.0286). Alternatively, expres sion of IGF-I in the stromal cells was related to metastasis at the ti me of diagnosis (P = 0.05), tumour diameter (P = 0.04), DNA ploidy (P = 0.07) and nuclear pleomorphism (P = 0.025), but it was without progn ostic significance in a univariate analysis (P > 0.1). In a multivaria te analysis, the conventional prognostic factors were superior to IGF- I expression in predicting the disease outcome, albeit expression of I GF-I in tumour stroma showed some independent prognostic significance in axillary lymph node negative tumours. The results suggest that IGF- I expression is related to malignant histopathological features in bre ast cancer, and expression of IGF-I has independent prognostic signifi cance in the early phases of the disease.