Haymaker Gene Expression in Malignant and Normal Gynecologic Tissues

We previously reported that cell lines established from human carcinomas and leukemias/lymphomas expressed high levels of an intracellular membrane-bound protein, Haymaker, whereas cell lines derived from non-malignant connective tissue cells and lymphoid cells expressed low levels of this gene product. To determine whether these findings reflect neoplastic transformation or, alternatively, tissue specificity, we examined by immunohistochemical and molecular methods the expression of Haymaker in gynecologic organs with and without tumor. A highly specific, affinity-purified rabbit polyclonal antibody against a 25-mer Haymaker peptide was used for immunohistochemical staining and morphometric analysis of 85 tissue specimens. Immunohistochemical studies demonstrate, for the first time, that Haymaker protein is highly expressed in epithelial cells of the endometrium of the normal uterus and to a somewhat lesser extent in the mucosa of the normal vagina and cervix, but is poorly expressed or absent in cells o...