Breast cancer (BC) represents the most frequent
neoplasm in women with a risk of incidence between 10% and 12%. The detection of
tumor associated and oncofetal
antigen re-expression in a variety of neoplastically transformed cell types has aided in the more precise diagnosis and prognostication of human
cancers. The homeobox (HOX) genes encode
proteins which contain a 61
amino acid DNA-binding homeodomain and are involved in the transcriptional regulation of other genes during normal onto- and histogenesis. The class I HOX genes are organized in four clusters on different chromosomes in humans, with a high conservation in the order of the genes within each of these clusters. Re-expression of HOX gene products has been reported in a wide variety of neoplastically transformed cells and it seems quite likely that the HOX genes represent yet another class of
oncofetal antigens involved in both normal development and
carcinogenesis, as well as
tumor progression. The expression pattern of three HOX gene products (HOX-B3, -B4, and -C6) was examined immunocytochemically in 11 human
breast carcinoma (BC) tissues. In all observed BC cases, HOX-C6 was present in over 90% of the neoplastically transformed cells (+4) demonstrating a high grade (A and B) staining intensity. The same expression pattern was defined for the other two observed
proteins (HOX-B3 and -B4; over 90% or +4 and a high grade staining intensity or A and B). Current treatment of BC encompasses the three "classic" modalities of
therapy: surgical resection,
radiotherapy, and
chemotherapy. Although advances have been made, we still face great difficulties in the treatment of this deadly human
neoplasm. Therefore, we are always seeking novel
tumor associated
antigens (TAAs), including
oncofetal antigens, to use as molecular targets in
cancer cell directed fourth modality
immunotherapy.