Comparative study of two androgen-induced markers (apolipoprotein D and pepsinogen C) in female and male breast carcinoma.

Background: Male breast cancer (MBC) is a rare tumor in comparison to the same disease in the female population (FBC). Classical prognostic factors (tumor size, node status, estrogen receptor positivity, histological grade) have a similar prognostic value in both tumors, but MBC seems to have a worse outcome. Several markers under estrogen control have been shown with a similar incidence in breast tumors of both sexes, while androgen-induced markers have been detected in a higher percentage of breast tumors in males.

Aims And Methods: Our purpose was to compare in 68 MBC and in 68 FBC the expression of Pepsinogen C (Pep C) and Apolipoprotein D (Apo D), two proteins under androgen control, by immunohistochemical methods.

Results: Pep C was expressed by 52 of 68 (76.4%) MBC patients, whereas 34 of 68 (50%) FBC showed positive staining. Apo D was expressed by 57 of 68 (83.8%) MBC patients, while 40 of 68 (41.2%) FBC stained positively. Differences between percentages of positive expression were significant (p<0.005 for Pep C; p<0.0001 for Apo D). Moreover, differences between expression levels of Pep C and Apo D in both populations of patients were significant. The mean value of Pep C was significantly higher in male breast tumors (HSCORE = 141.3) than in the females (HSCORE = 80.3) (p<0.0001). Similarly, Apo D mean value was significantly higher in MBC (HSCORE = 161.5) than in FBC (HSCORE = 102.3) (p=0.006).

Conclusion: These differences can open the field of a more selective hormonal therapy that should not be based on estrogen receptor status only, but also on androgen receptor status.