Telomere elongation frequently observed during tumor metastasis.

Changes in the number of telomere repeat arrays have been examined during metastasis of two mouse tumor cell lines. Telomeres were detected as bands and a smear by pulsed-field gel electrophoresis and gel-hybridization using (TTAGGG)4 as a probe. Very long size variants of telomeres were frequently observed in metastatic nodules. This suggests that at least some of the tumor cells have an ability to elongate telomeres. This elongation may compensate for the continuous loss of telomere repeats due to cell divisions, which would eventually lead to cell death.