EXPRESSION OF HLA-D SUBLOCI DR AND DQ BY BREAST CARCINOMAS IS CORRELATED WITH DISTINCT PARAMETERS OF FAVORABLE PROGNOSIS

The expression of HLA-D region products HLA-DR, DQ and DP by primary breast carcinomas was examined for its relationship to standard prognostic parameters. A positive correlation was found between the expression of HLA-DR and the differentiation state of the tumour (P = 0.02) and the expression of progesterone receptors (P = 0.002), two parameters which are associated with good prognosis and with each other. No correlation was seen between these parameters and the expression of HLA-DQ or HLA-DP. In contrast, tumour diameter was inversely correlated with the expression of HLA-DQ (P = 0.0004) although no association was observed between this parameter and HLA-DR expression. Essentially all HLA-DQ positive tumours had a diameter of less than 2 cm although these represented only 50% of the tumours of this size examined. These data show that in breast carcinomas HLA class II expression is correlated with several distinct parameters of good prognosis and suggest that HLA-DQ expression may define a subtype of T1 tumours.