Abstract
PurposeAccurate monitoring of predictive markers is of utmost importance as oncological treatment decisions almost entirely depend on these factors. In this study, we conducted a quality control assessment on hormone receptors, Her2 status, Ki67 Labelling Index (LI) and histological grading in breast cancer over 4 years (2015–2018).MethodsAltogether 2214 consecutive breast cancer cases were included. Data on estrogen (ER) and progesterone receptors (PR), Her2 and Ki67, were available in all cases and were tested mostly on preoperative biopsies, in selected cases on postoperative surgical specimens. ER, PR, and Ki67 were assessed with immunohistochemistry (IHC), Her2 status with IHC and fluorescence in situ hybridization.ResultsER/PR were positive in 74–79% cases, ER/PR/Her2 negative in 6.16–10.70% and Her2 positive in 11.49–13.88%/year. Ki67 had median values as 15–17.5% in ER/PR-positive cases, 55–60% in triple-negative cases and 30–32.50% in Her2-positive cases. Histological grading distribution for well (G1), moderately (G2) and poorly (G3) differentiated carcinomas was 15.8–19.1% for G1, 54.2–54.8% for G2 and 21.7–23.7% for G3 cases. Variation in yearly distributions was not significant in any of these markers.ConclusionsPredictive markers displayed a yearly similar distribution in breast cancer cases independently of grading or of intrinsic subtypes. These results point to a qualitative high performance of predictive marker assessment in breast cancer, corresponding to expected on average positivity rate per marker and per year. It is recommended to monitor positivity rate of ER, PR, Ki67 and Her2 yearly or periodically to comply with quality assurance requirements.
Highlights
Breast cancer is the most common invasive cancer and the leading cause of cancer-related deaths in women worldwide (McGuire et al 2015)
fluorescence in situ hybridization (FISH) Her2 positivity rate showed a slight variation in these 4 years, varying between 10.8 and 16.21% per year
Regarding HER2 status, this study shows that concordance rates of FISH and IHC assessments of HER2 have significantly improved compared to earlier reports among other from the same institution (Varga et al 2013)
Summary
Breast cancer is the most common invasive cancer and the leading cause of cancer-related deaths in women worldwide (McGuire et al 2015). One of the main pillars of breast cancer management is targeted therapy (Slamon et al 2011). There is a wide range of biomarkers being expressed by different breast cancer subtypes. Targeted therapy is mainly planned and based on the profile of biomarker expression, which basically comprise ER/PR Her and Ki67 Labelling Index (LI) (Hicks and Tubbs 2005). The link between HER2 overexpression/amplification and breast cancer growth and development has been an important hallmark in targeted breast cancer therapy (Slamon et al 1987). HER2 is a transmembrane tyrosine kinase receptor expressed in approximately 20% of invasive breast cancer, accounting for aggressive phenotypes, early metastasis and lower rate of disease-free and overall survival HER2 is a transmembrane tyrosine kinase receptor expressed in approximately 20% of invasive breast cancer, accounting for aggressive phenotypes, early metastasis and lower rate of disease-free and overall survival (Slamon et al. Vol.:(0123456789)
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