Primary small cell anaplastic carcinoma of the breast diagnosed by fine needle aspiration cytology: a case report

Telomerase, a ribonucleoprotein that adds telomeric repeats onto chromosome ends, is involved in telomere length maintenance and permits unlimited cell proliferation. We examined the possibility that higher telomerase activity is associated with the replicative phase of the cell cycle using gastric cancer cell lines treated with anticancer drugs. Telomerase activity increased at the time point of S-phase accumulation in NUGC-3 cells (5 x 10(5) cells/ml) incubated with CDDP (0.5 microgram/ml), paclitaxel (0.01 microM), or VP-16 (1 microM) and in MKN-28 cells incubated with CDDP. When these cell lines were incubated with 5-fluorouracil (10 microM) or CPT (0.1 microM), the increase of telomerase activity preceded the S-phase accumulation. Our results suggest that telomerase activity be regulated by the cell cycle.