Can the HLA phenotype be used as a prognostic factor in breast carcinomas?

There is evidence indicating that change in the expression of HLA-ABC antigens can modulate the biological behavior and metastatic potential of certain neoplasms. We studied 15 samples of normal breast epithelium, 94 breast carcinomas and 24 benign and pre-malignant lesions of the mammary gland. All cases of normal breast epithelium and non-malignant lesions presented high levels of expression of class-I antigens. In contrast, 22 out of 94 carcinomas showed a reduction in the level of expression and a heterogeneous pattern. In addition, 31 tumors were considered negative for HLA-class-I expression, and 6 cases showed selective loss of HLA-ABC: 2 tumors for HLA locus A, and 4 for HLA locus B. We found a direct relationship between patient survival and HLA-negative phenotype (p less than 0.001), as well as between histological grade of malignancy and the level of expression of class-I antigens (p less than 0.0005). Moreover, the presence of class-I molecules was significantly related to tumor ploidy (p less than 0.005). Our results lead us to conclude that HLA-ABC-negative tumors have a higher metastatic potential and greater clinical aggressiveness: patients with carcinomas exhibiting low HLA expression have more lymph-node metastases (p less than 0.02) and achieve shorter survival times (p less than 0.001).