Male Breast Carcinoma

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breast cancer improved over the time period from 1975-2005" (Korde et al 2010). Overall, these studies are quite small in comparison with population based studies of women.

The most predominant male histological type cancer is invasive ductal carcinoma and pure invasive micropapillary is rare between men and women. This study produced no findings of pure invasive micropapillary carcinoma, but did reveal 8 mixed type which could indicate a similarity between male and female invasive micropapillary carcinomas (Zhou 2004). Also notably rare in men is invasive lobular carcinoma. While no patients in this study exhibited such a diagnosis, 1 case in this study cohort was diagnosed with invasive papillary carcinoma and 8 papillary carcinomas. Conversely suggesting that the papillary architecture is commonly presented in male carcinoma as well (Zhou 2004). Burga et al suggests that discrepancies in male and female histological type distribution play a valuable role in the pathogenesis of breast carcinoma and further studies are needed.

This study found luminal subtypes to be most abundant. With subtype A being more frequent than luminal B, based on IHC surrogate definitions (Zhou et al). Similar results were concluded with a study preformed by Kornegoor et al. These studies both relied on Ki-67 index when determining molecular subtyping. "The present study, one of the largest series of male breast cancer published until now, demonstrates that luminal A and to a lesser extent luminal B types represent the vast majority of breast cancer in men" (Kornegoor 2011).

The basal-like subtype is very rare in male breast cancer and only two patients exhibited this classification within Zhou et al study group. Each were diagnosed as secretory carcinomas, which is notable and should be distinguished separately from conventional basil like carcinomas. Secretory breast carcinoma is a rare breast cancer often affecting children. One study preformed by Li D et al reveals that, "secretory breast carcinoma is a distinct subset of basal-like carcinoma, with expression of basil-like markers" (2012). Further studies are required to help determine the prognostic characteristics of basil-like markers and their expression patterns with relation to secretory breast carcinomas.

Zhou’s study group produced positive staining of GCDFP15 at 57.9% and MGB staining at 52.6%, which is similar to other studies results at around 50%. Many similar studies have been completed and often have conflicting results, suggesting that results correlating the expression of GCDFP15 and MGB were variable and inconsistent (Zhou et al).

FOXP1 expression is correlated with a high survival rate and is positively associated with hormone receptor status. Additionally, it is suggested that it may play a role as ER co-regulator. This study cohort had high frequencies of expression of ER and PR, in turn causing the relationship between FOXP1 and hormone receptors not to be determined (Zhou et al). Much is to be determined about the suggestions and roles FOXP1 and its effect, especially considering its association with clinical survival and importance in both male and female breast carcinoma. A different study preformed by Fox et al suggested that "FOXP1 as a potential ER co-regulator in human breast carcinoma and suggests that it may also independently regulate additional important pathways that control the progression of breast cancer" (2004).

Conclusion

This review of literature continued to reveal pertinent information pertaining to molecular subtypes and immunohistochemical characterization in male breast carcinoma in the Chinese population, as well as insight on the disease as a whole. However limitations occur such as quantity of study cases and incomplete follow up information. Further testing and complete data pooling needs are required for a better understanding of all male breast carcinoma (Zhou et al). Furthermore, "Current efforts at pooling epidemiologic data, clinical information, and tumor specimens will lead to a greater understanding of the etiology of this disease...international collaborations will also facilitate the future planning of successful clinical trials that can address essential questions in the treatment of male breast cancer" (Korde 2010).

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