Expression and clinical significance of apolipoprotein D in male breast cancer and gynaecomastia

Background: Apolipoprotein D (Apo D) is a protein component of the human pl asma lipid transport system which is present in benign and malignant human breast tissues. This study analysed the expression of Apo D in men with gyn aecomastia or breast cancer, and evaluated its use as a prognostic marker i n breast cancer. Methods: Immunohistochemical expression of ApoD was examined in specimens f rom 15 men with gynaecomastia, two with in situ breast carcinoma and 68 wit h invasive male breast cancer. Median follow-up in patients with breast can cer was 44 months. Results: All gynaecomastia specimens, both in situ carcinomas and 57 invasi ve carcinomas (84 per cent) stained positively for Apo D, Apo D values were significantly correlated with axillary node involvement and histological g rade of the tumours. In men with breast cancer univariate analysis showed a statistical association between node status and ApoD content with relapse- free survival (P < 0.001) and overall survival (P < 0.05). Cox multivariate analysis showed that Apo D was a significant indicator of relapse-free sur vival (P = 0.0089), but node status was the strongest factor able to predic t both relapse-free (P = 0.0336) and overall (P = 0.0346) survival. Conclusion: Apo D was expressed in gynaecomastia and a high percentage of m ale breast carcinomas. There was a positive association of Apo D content in male breast tumours with favourable outcome. Apo D expression was a signif icant independent indicator of relapse-free survival in male breast cancer.