Utilization of Cell-Transferred Cytologic Smears in Detection of EGFR and KRAS Mutations on Non-Small Cell Carcinoma of Lung and Comparison to Formalin-Fixed Tissue
Joseph Eaton, Kelly Jones, Liang Cheng, Melissa Randolph, Harvey Cramer, Howard Wu. Indiana University, Indianapolis, IN
Background: The presence of EGFR and KRAS mutations can be used to predict response to treatment in patients with non-small cell lung cancer (NSCLC). Fine needle aspiration (FNA) can provide cellular material which may be used for such analysis. Formalin-fixed cell blocks (CB) have been used for this purpose; however, CBs sometimes lack adequate cellularity even when the direct smears are highly cellular. The aim of this study is to assess the utilization of the cell transfer technique (CTT) to obtain adequate cellular materials from the direct FNA smears for EGFR and KRAS mutation.
Design: A computerized search of the laboratory information system was performed. FNA cases diagnosed as NSCLC and had previous EGFR and KRAS mutation tests performed on the corresponding CB or biopsies were identified. Tumor cells from both ethanol-fixed Papanicolaou-stained and air-dried Diff-Quik stained direct smears were removed using CTT to submit for EGFR and KRAS mutation testing. The results were compared to those performed on the archived formalin-fixed paraffin embedded (FFPE) corresponding CB (10 cases) and core biopsy (8 cases).
Results: A total of 18 cases including 10 cases for KRAS and 8 cases for EGFR were included in the study. For KRAS, 4 mutations and 5 wild types (WT) showed correlation between CTT and FFPE. In one case, the FFPE showed KRAS mutations while the CTT demonstrated WT result. Re-reviewing the original direct smears from this case showed only scant tumors cells present in a background of abundant benign bronchial cells. EGFR tests demonstrated positive correlation between CTT and FFPE in all 8 cases including 4 mutations and 4 wild types. Both air-dried and ethanol-fixed smears are adequate for the test.
Conclusions: Cell-transferred technique is a feasible method to obtain cellular materials from archived FNA direct smears for EGFR and KRAS mutational tests. There is high agreement rate between the CTT and FFPE tissue. Either air-dried or ethanol-fixed smears can be used successfully for the test. The selection of adequately cellular areas with tumor cells is very important for the correct mutational status.
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 66, Tuesday Afternoon