Immunohistochemical Survey of Invasive Ductal Carcinoma of the Breast, using ER, PR, HER2 and KI-67 biomarkers, in Uyo, Nigeria

Background: Breast's Invasive Ductal Carcinoma (IDC), which is the commonest type of malignancy in females worldwide, can be characterized using immunohistochemistry in view of personalized cancer therapy. In this study, we aimed to determine the pattern of immunohistochemical profiles of IDC using oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 receptor (HER2) and proliferative index (Ki-67) biomarkers in our tertiary healthcare facility in Uyo, Akwa Ibom State, Nigeria given the dearth of its data in our environment. Materials and methods: We carried out a retrospective hospital-based immunohistochemical study of archival IDC tissue blocks over a four- and half-year period. Using systematic random sampling method, 64 formalin fixed paraffin embedded (FFPE) IDC tissue blocks were selected for this study. We carried out immunohistochemical evaluation using ER, PR, HER2 and Ki-67 biomarkers. Subsequently, we presented the results and classification schemes as text, tables, graphs, and photomicrographs. Results: We found that the proportion of expressions were ER-negative (88.7%), PR-negative (87.3%), HER2-negative (68.3%) and Ki-67 (<20%) being 83.6% respectively. The immunohistochemical-based classification which was done using combined immunohistochemical profiles of ER/PR/HER2 and ER/PR/HER2/Ki-67 biomarkers respectively, revealed five immunohistochemical-based subtypes. These subtypes were ER-positive luminal A (ER+/±PR+/HER2-) [5.56%], ER-positive luminal B (ER+/±PR+/HER2+) [5.56%], HER2-overexpression (ER-/±PR+/HER2+) [16.66%], Triple negative (ER-/PR-/HER2-) [66.67%] and Unclassified subtypes (ER-/PR+/HER2-) [5.56%]. Furthermore, these five subtypes were further subcategorized into low (Ki-67 <20%) and high (Ki-67 ≥20%) proliferation subtypes accordingly. Conclusion: The commonest pattern of immunohistochemical profile expression of IDC in Uyo was found to be the Triple negative subtype.

Assessment of MIB1 (Ki-67) Labeling Index and Correlation with Other Well Established Prognostic Factors in Breast Cancer

PURPOSE: The MIB1 labeling index is new method utilizing a monoclonal antibody against Ki-67 antigen and useful for evaluating the proliferation rate in breast cancer due to its ease of use and reliability. We compared the MIB1 labeling index to other, well established prognostic factors and assessed the prognostic value of MIB1 in 564 breast cancers. METHODS: The MIB1 (Ki-67 equivalent monoclonal antibody) proliferation rate, MIB1 labeling index, was determined in formalin-fixed, paraffin-embedded tissue specimens of 564 primary breast cancer patients who underwent surgery between March 1998 and February 2000 at Seoul National University Hospital. The clinicopathologic characteristics of the primary tumor such as age, tumor size, histologic type, nuclear grade, histologic grade, hormone receptor status and various tumor markers (p53, c-erbB-2, bcl-2) were compared with the value of the MIB1 labeling Index. RESULTS: The mean value of MIB1 labeling index was 6.9. MIB1 labeling index was correlated to younger age (p= 0.011), histologic types, low nuclear grade (p=0.0001), high histologic grade (p=0.0001), p53 positive (IDC) (p=0.0001), c-erbB-2 positive (DCIS) (p=0.01), comedo type (DCIS) (p= 0.001) and inversely correlated to hormone receptor positivity (p=0.0001), bcl-2 positive (IDC) (p=0.001). No correlation was found in tumor size, lymph node status and c-erbB-2 positive (IDC). CONCLUSION: The MIB1 labeling index correlated well with well-established poor prognostic factors. The MIB1 labeling index may be an important prognostic determinant in breast cancer.