Diagnostic utility of CD205 in breast cancer: Simultaneous detection of myoepithelial cells and dendritic cells in breast tissue by CD205.

Background: CD205 can be used to detect myoepithelial cells (MECs) and dendritic cells (DCs) in breast tissue. However, the usefulness of CD205 immunostaining in the pathological diagnosis of breast tumors is not fully understood. The objective of this study was to re-evaluate CD205 co-expression with other MEC markers, such as p63 and CD10, in nonneoplastic and neoplastic breast tissue and to evaluate its pathological diagnostic utility in these types of breast cancer.

Material And Methods: Nonneoplastic breast tissue samples with a terminal duct lobular unit and duct were obtained from fibroadenoma and mastopathy patients. Neoplastic breast tissue samples included ductal carcinoma in situ (DCIS) (n=43) and invasive ductal carcinoma (IDC) (n=60), including the tubule-forming type (n=20). These specimens were investigated by CD205, p63, and CD10 immunostaining.

Results: In addition to p63 and CD10, CD205 was expressed on MECs in nonneoplastic breast and DCIS tissue samples; CD205 was simultaneously detected on DCs that had infiltrated DCIS and IDC tumor nests. CD205 was expressed on cancer cells themselves in only 7.3% of the breast cancer samples. The number of intratumoral CD205⁺ DCs in tubular IDC was significantly higher than that in DCIS (P<0.01).

Conclusion: Because CD205 was simultaneously detected on MECs and DCs in the same breast tissue sections, it may be useful for distinguishing tubular IDC from DCIS.