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

Abstract

AimsHistological 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 resultsProliferative 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.ConclusionsImmunohistochemical 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.