Therapeutic effects of Vernonia amygdalina on the expression of hormone and HER2 receptors in 7, 12-dimethylbenz(a)anthracene-induced breast tumours in obese and non-obese Wistar rats

•The immunohistochemical profile of breast tumours experimentally induced with 7, 12-dimethylbenz (a) anthracene (DMBA) in obese and non-obese Wistar rats is triple-negative and triple-positive respectively.•Vernonia amygdalina is generally associated with a reduction in the proliferation of cancer cells regardless of the different immunohistochemical profiles of the obesity- and non-obesity- associated breast tumours seen in the two study groups.•Vernonia amygdalina is also associated with the reversal of the increased ER, PR and HER2 expressions seen in the triple-positive breast tumours of the non-obese rats.