Inhibitory effects on the viability and proliferation of breast cancer cells. (A) The cells were treated with VaM for 24 or 48 h, and cell viability was assessed using the MTT assay. (B) Colony formation assay was performed to evaluate the inhibitory effect of VaM on cell proliferation. Cells treated with or without VaM were reseeded, and after 14 days, the colonies were stained and counted. The graph shows the quantification of stained colonies relative to that of the untreated group. The data were quantified based on an untreated group of each cell. * p < 0.05, ** p < 0.01, *** p < 0.001, and **** p < 0.0001 compared to the condition with zero treatment concentration. The results are presented in the bar chart as the mean ± SD of the three independent experiments. Yellow circles represent the results of three independent experiments.