Barr body distribution and estrogen receptor protein in mammary carcinoma.

The study was undertaken to investigate the relationship between Barr body distribution and estrogen receptor protein content of mammary carcinoma. The proportion of cells with one or more Barr body was determined in 105 specimens of mammary carcinoma from Guard stained imprints. Receptor protein content of the specimen was measured by the dextran charcoal method and compared with histopathologic features of the carcinomas. Primary carcinomas with Barr bodies in more than 10 percent of tumor cells were more likely to have higher levels of receptor protein than those with a lower proportion of Barr body containing cells (P less than 0.005). The results obtained for primary carcinoma may explain why patients with carcinomas that have a high proportion of Barr body positive cells are more likely to respond to hormonal therapy. Furthermore, these observations, when correlated with other available data about ERP suggest that an X-chromosome is involved in the synthesis of and/or carries the locus of action for estrogen receptor protein.