Study the apoptosis in lymphocytes from cervical cancer patients receiving radiation therapy

Abstract

Apoptosis or programmed cell death in the peripheral leukocytes can be induced by low dose irradiation. In this cross section designed study, we studied the percent apoptotic activity found in lymphocytes obtained from peripheral blood of the cervical cancer patients who had received radiation therapy at King Chulalongkorn Memorial Hospital. A group of five patients in each stage of cervical cancer and at the designed posttreatment intervals were included. Blood samples were taken from individual patient of each group before the radiation therapy and after completion of radiation therapy at 1 month, 3 months, 1 year, and 5 years. The control samples were collected from healthy female blood donors at National Blood Bank, The Thai Red Cross Society, with age matched to each group of pretreated cervical cancer patients. The lymphocytes were separated and irradiated with 0.5 Gy Co radiation to induce apoptosis. The apoptotic cells at 24 and 48 hours afterradiation induction were detected by in situ terminal deoxynucleotidyl transferase (TdT assay) and counted under fluorescence microscope. Both the apoptotic index and percent apoptotic activity were calculated. The results showed that the percent apoptotic activity in the control groups was higher than the pretreated cervical cancer patients (p=0.001), but it was not differed from the 5 years posttreated groups (p=0.079). Comparison of the percent apoptotic activity in pretreated groups to posttreated groups at 1 month, 3 months, 1 year, and 5 years resulted in an increment of the percent apoptotic activity in the posttreated groups without any statistical significance. Higher percent apoptotic activity was observed in patients with early stage cervical cancer than late stage (p=0.024). In conclusion, it may be possible to apply the percent apoptotic activity as a parameter to detect any recurrent cancer in long term follow up.