The effect of surgical biopsy on the cell production rate of a murine tumour

The rate of cell production of a mammary adenocarcinoma following surgical biopsy has been investigated using vincristine sulphate as a metaphase arrest agent. Small implants of the tumour were implanted into the inguinal region of young mice of both sexes and were seen to have a constant rate of cell production both between different tumour generations and during tumour growth. Such a constant rate of tumour cell production provides an extremely useful model for exploring the effects of surgical biopsy. Measurements of the cell production rate showed a 60 per cent decrease for the first 48 hours following biopsy after which recovery ensued to reach control levels again. Sham‐anaesthetized controls and sham‐resected controls demonstrated none of these changes. Similar depression in the rate of cell production was seen following biopsy of one tumour in mice bearing bilateral tumours. The 48‐hour depression was observed both in the ipsilateral remnant tumour and in the contralateral implant which has not been biopsied.