Immunocytochemistry using Liquid-based Cytology: A Tool in Hormone Receptor Analysis of Breast Cancer.

Context: Efficacy of immunocytochemistry (ICC) in determining molecular biomarkers like estrogen receptor (ER), progesterone receptors (PRs), and human epidermal growth factor receptor-2 (HER2).

Aims: To evaluate biomarkers using ICC in breast cancer as per American Society of Clinical Oncology/College of American Pathology (ASCO/CAP) guidelines.

Settings and Design: The study was conducted over a period of 2 years from September 2012 to August 2014 and is the first such study in eastern India.

Materials and Methods: Fine needle aspiration cytology (FNAC) was done for suspected cases of breast cancers and slides were prepared using ThinPrep (TP) technology of liquid-based cytology (LBC) for ICC and corresponding biopsy specimens were processed as formalin fixed paraffin embedded (FFPE) sections for comparison. Both the LBC slides and tissue sections were subjected to immunostaining for ER, PR, and HER2. ICC was evaluated by Allred Scoring and IHC by Quick Scoring.

Statistical Analysis Used: Statistical analysis done by Wilconxon Signed rank test on the SPSS program, Chicago, Illinois, USA. The results of ICC and IHC were compared by evaluation of sensitivity, specificity, kappa-value (k-value), positive predictive value (PPV), and negative predictive value (NPV).

Results: The comparison of ICC with immunohistochemistry (IHC), ER, and PR showed very good correspondence rate, sensitivity, specificity, NPV, PPV, and agreement with k-value; whereas for HER2 the results were only good.

Conclusion: ICC using LBC can be a useful tool in assessing biomarkers in advanced cases of breast cancer where surgery is not possible or cases where ASCO/CAP guidelines for management are not followed.