Role of LINE-1 Retrotransposons in Human Breast Cancer.
Final rept. 27 Oct 92-30 Sep 95,
ARMED FORCES INST OF PATHOLOGY WASHINGTON DC
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The human LINE-1 retrotransposon L1Hs is known to cause mutations by inserting into genes and inactivating them. The element is expressed in many breast tumors and breast tumor cell lines, suggesting that L1Hs-induced mutations may play some role in this malignancy. Prior evidence suggested that unmethylated L1Hs elements are transcriptionally active. Therefore, we used the inverse polymerase chain reaction technique to clone 12 elements that are unmethylated in the breast tumor cell line, T47D. Characterization of these clones shows that some elements are umnethylated in other breast cancer cell lines, but are methylated in several normal breast cell lines that do not express L1Hs. In addition, L1Hs elements that are unmethylated in malignant breast cells are usually methylated in malignant germ cells that express L1Hs. Our results suggest the possibility that different subsets of active L1Hs elements are expressed in different cancers.
- Medicine and Medical Research
- Anatomy and Physiology