Alternative lengthening of telomeres (ALT) is a telomere maintenance mechanism used by approximately 10% of human cancers, including poor prognosis childhood and adult cancers for which development of better treatments is a priority. Currently there are only about ten published ALT+ cancer cell lines available for research, only four of which are available from international repositories. The development of the C-Circle Assay has made it possible to accurately and conveniently test a large number of cell lines for ALT activity. We have tested a panel of 297 cancer cell lines from the American Type Culture Collection (ATCC) with the C-Circle Assay for ALT and identified 34 new ALT+ cell lines. Importantly, we have identified for the first time ALT+ cancer cell lines derived from breast carcinoma, hepatocellular carcinoma, melanoma and leukemia. The overall proportion of ALT+ cancer cell lines was 11.4% (n = 297), which included 19.5% of leukemia (n = 46), 19.0% of melanoma (n = 21), 12.7% of non-small cell lung carcinoma (n = 53) and 3.3% of breast carcinoma (n = 37) cell lines. These results identify additional cancer cell line resources for research into the ALT mechanism, including cell lines from cancer types where ALT has not previously been studied in detail.

Citation Format: Andrei G. Malykh, Jonathan R. Doyle, Fang Tian, Joyce HY Lee, Jeremy D. Henson, Roger R. Reddel. Identification of new alternative lengthening of telomeres (ALT)-positive cancer cell lines using the C-circle assay. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3768. doi:10.1158/1538-7445.AM2015-3768