Aim: To correlate between immunohistochemical (IHC) expression of microfibril associated protein 5 (MFAP5) in primary invasive duct carcinoma of no special type (IDC/NST) of the breast and corresponding lymph node metastasis (LNM). Methodology: A retrospective, cross sectional study was conducted. Material included 106 samples of IDC/NST. Each sample has been represented by two tissue cores in tissue microarray (TMA), one core from primary breast lesion and the other core from corresponding LNM. Diagnosis, grade, and subtype documented in patients' records had been confirmed by regular hematoxylin and eosin stain examination. Additionally, hormone receptor IHC profiles were obtained from archives and reassessed. Immuno-stained slides using primary antibody against MFAP5 were prepared and evaluated via a three-tiered system for MFAP5 intensity of staining in all samples (Negative/ weak- Moderate/ low-Strong/ high). Results: Statistical analysis of all IHC stained samples revealed a statistically significant positive correlation between MFAP5 expression in LMN and higher grades of primary tumor, specifically with high scores of both tubular formations and nuclear pleomorphism. Additionally, such significant positive correlation was evident with ER expression score in primary tumor, and with Ki 67 expression in primary tumor. Conclusion: Findings obtained from our study supported considering MFAP5 overexpression in primary IDC/NST as a poor prognostic factor. We also proposed MFAP5 as a prognostic IHC marker and a potential hormonal therapy (anti estrogens) responsiveness marker in IDC/NST to be assessed in both primary lesion and metastatic nodal deposits.

Invasive duct carcinoma of no special type, Breast cancer, MFAP5 Lymph node