Preliminary evidence for curative effect of BCG on chemically induced carcinoma of mammary gland of female albino rat

The present study describes the possible curative effect of bcg on chemically induced breast cancer in female albino rats. five groups,each of ten spague dawley adult female albino rats were administered with 100 μg 7,12 dimethyl benz [α] anthracene (dmba) once a week and 10 μg 12-0 tetra deconal phorbol b acetate (tpa) twice a week,for twenty and eighteen weeks,respectively,to allow development of breast cancer. another group of ten rats was injected 0.1 ml acetone intraductally through the nipple three times a week for twenty weeks which served as control group. four of these five groups were injected 0.5 mg bacillus calmette guerin (bcg) once a week for six weeks. one out of these five groups of animals and control were sacrificed after twenty weeks whereas bcg was administered for another six weeks to the remaining four groups. these experimental animals were sacrificed one,four,eight and tweleve weeks after the last dose of bcg. the breast tissue was removed,fixed and processed for histological study. the breast tissue from animals treated with dmba and tpa showed hyperplasia and malignant changes,whereas those sacrificed one week after bcg treatment manifested malignant and degenrating cells. those sacrificed after four weeks showed complete absence of malignant cells,whereas the ones sacrificed after eight weeks showed recurrence of mild hyperplasia and malignant changes. the rats which were sacrificed after twelve weeks showed hyperplasia and malignant cells indicative of recurrence. it was,therefore,concluded that bcg treatment reversed the chemically induced malignancy of the breast,though recurrence was observed eight and tweleve weeks after the treatment with bcg. further work is needed to evaluate the possibility and complete cure of the condition using bcg regime with modifications. copyright 2012 zoological society of pakistan.