[718] Detection of Chromosomal Anomalies in Colon Biopsy Specimens Using Fluorescence In Situ Hybridization (FISH) – A Pilot Study

J Qian, D Hossain, G Sadasivan, DG Bostwick. Bostwick Laboratories, Glen Allen, VA

Background: Colorectal carcinoma is the third most common cancer diagnosed in the United Sates. Using current histological techniques, differentiating between adenoma and carcinoma can be challenging in certain cases, and identifying those adenomas with a high risk for progression to cancer is not possible. In this study, we sought to develop a FISH test to aid in the differential diagnosis of adenoma and adenocarcinoma.
Design: We used FISH with centromere-specific probes for chromosomes 7, 15, 18, and 20 to evaluate chromosomal anomalies in colon biopsy specimens diagnosed as benign (31), adenoma (25) and adenocarcinoma (26). The FISH signals were enumerated in 50 cells per case, and the chromosomal anomalies were correlated with pathologic findings.
Results: Numeric chromosomal anomalies were found in 0% (0/31) of benign, 64% of adenoma (16/25), and 92% (24/26) of carcinoma specimens (for each pair The mean percentage of cells with chromosomal changes was 55% in cancer specimens, significantly higher than that in adenoma (18%, p< 0.0001) and benign mucosa (2%, p< 0.0001). The most frequent chromosomal anomaly was gain of chromosome 7. FISH anomalies had an overall sensitivity of 81% and specificity of 88% for the distinction of adenoma from carcinoma.

Cancer vs. Benign92%100%0.96
Cancer vs. Adenoma81%88%0.84
Cancer vs. Non-Cancer92%71%0.82
Cancer/Adenoma vs. Benign78%100%0.89
Adenoma vs. Benign64%100%0.82

Sensitivity Specificity ROC Cancer vs. Benign 92% 100% 0.96 Cancer vs. Adenoma 81% 88% 0.84 Cancer vs. Non-Cancer 92% 71% 0.82 Cancer/Adenoma vs. Benign 78% 100% 0.89 Adenoma vs. Benign 64% 100% 0.82
Conclusions: Multi-target FISH appeared to be useful for the differential diagnosis of colonic adenoma from adenocarcinoma, with a high level of sensitivity and specificity. In addition, adenoma with high level of FISH-detected chromosomal anomalies may require close clinical follow-up.
Category: Gastrointestinal

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 54, Wednesday Morning


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