Measurement of tritiated thymidine labeling index by incubation in vitro of surgically removed cervical cancer.

Autoradiographic study was made on 24 cases of uterine cervical tumor, including 22 cases of squamous cell carcinoma, using a technique of in vitro labeling of surgical specimens with tritiated thymidine (3H-TdR) under hyperbaric oxygen. Labeling index of the cervical cancer ranged from 8.7 to 30.4% and was well correlated with the histological subtypes (spinal, transitional, and basal cell types). The upper limit of the growth fraction was also estimated from the general relationship between phase lengths. The necessity of sufficient oxygen tension for the S-phase cells to effect synthesis of DNA was stressed.