(A) Pictorial representation of tumour size ex situ and in situ LA‐7 rat syngenic mammary tumour model at 25 days of oral administration of vehicle (n = 4), DTPEP (10 mg/kg, n = 4 and 20 mg/kg, n = 4) and TAM (20 mg/kg, n = 4). (A, I). DTPEP reduces metastatic nodules in lung of LA‐7 rat mammary tumour model. (B). DTPEP induces loss of ex situ tumour weight, (C). relative tumour weight and (D) in situ tumour volume. Oral administration of DTPEP does not disrupt absolute organ weight (E), relative organ weight (F), total body weight (G) and total body weight gain (H). Statistical analysis of each parameter for the compound‐treated groups was compared with non‐treated groups using one‐way ANOVA (non‐parametric) with Newman‐Keuls post hoc test. The difference was considered statistically significant if *P < .05. **P < .01 and ***P < .001 vs control