Histological grading of breast cancer on needle core biopsy: the role of immunohistochemical assessment of proliferation

Kwok T C, Rakha E A, Lee A H S, Grainge M, Green A R, Ellis I O & Powe D G (2010) Histopathology 57 , 212–219 Histological grading of breast cancer on needle core biopsy: the role of immunohistochemical assessment of proliferation Aims: Histological grade assessed on needle core biopsy (NCB) moderately concurs with the grade in the surgical excision specimen (SES) (κ‐values between 0.35 and 0.65). A major cause of the discrepancy is underestimation of mitoses in the NCB specimen. The aim was to determine the best method of assessing proliferation on NCB. Methods and results: Proliferative activity of 101 invasive carcinomas of the breast on NCB and SES was assessed using mitotic counts on routine haematoxylin and eosin (H&E) sections and immunohistochemical markers Mib‐1 and phosphorylated histone H3 (PPH3). H&E mitotic count in SES was considered as the gold standard. H&E mitotic count was found to be underestimated on NCB when compared with that in SES ( P < 0.001), but no significant difference was detected between NCB and SES regarding Mib‐1 ( P = 0.13) or PPH3 ( P = 0.073). Using receiver–operating characteristic curve, Mib‐1 on NCB was found to agree with the gold standard significantly better than routine H&E on NCB. Conclusions: Immunohistochemical markers in NCB showed better concordance with H&E mitotic count in SES (gold standard) than routine H&E mitotic count in NCB. Further refinement of cut‐offs and scoring methods is needed.