Early-in-life dietary zinc deficiency and supplementation and mammary tumor development in adulthood female rats

Amounts of tissue magnesium and some trace elements in cats with mammary tumors related to various clinicopathological parameters

BACKGROUND

Mammary tumors are one of the major malignancies seen in cats. Researchers have indicated the similarity between the epidemiological and clinicopathological patterns of feline mammary tumors and human breast cancer (HBC). In recent years, the investigation of trace elements in cancer tissues becomes prevalent in HBC due to the role of these elements in biochemical and physiological processes. This study, it is aimed to evaluate some trace elements in feline mammary tumors according to clinical and pathological findings.

METHODS

A total of 60 tumoral masses from 16 female cats with mammary tumors were included in the study. The study groups were formed according to histopathology as malignant epithelial tumor (MET; n = 39) and hyperplasia and dysplasia (H&D; n = 21). Copper (Cu), Iron (Fe), Magnesium (Mg), Manganese (Mn), Selenium (Se) and Zinc (Zn) trace elements in mammary tissues were analyzed by using an inductively coupled plasma-optical emission spectrophotometer.

RESULTS

The mean age and weight of the cats were 11.75 ± 0.75 years and 3.35 ± 0.21 kg; respectively. Eleven of 16 cats were intact whereas the rest of them had been spayed. Metastases were observed in 10 cats. Tissue Mg level in group MET was significantly higher than in group H&D (P < 0.01) while the other elements had not significant differences between the groups. In group MET, analyzed elements were not statistically significant related to the inflammation, ulceration and invasion to the peripheral muscle (P > 0.05). However, tissue Fe level was significantly higher in T2 than in T3 (P < 0.05). The mean levels of tissue Fe, Mg and Mn had significant differences related to histological grading as P < 0.01, P < 0.05 and P < 0.001; respectively. A mild to severe correlation was found between tissue Zn and Se, Cu, Fe, Mg, and Mn levels.

CONCLUSION

Tissue Mg and some trace elements were evaluated in feline mammary tumours in regard to various clinicopathological parameters. Tissue Mg level was sufficient to differentiate the malignant epithelial tumors from hyperplasia and dysplasia. However, Mn and Se tended to distinguish different tumor types. Tissue Fe, Mg and Mn had significant differences related to histological grading. Also, the Fe level was significantly higher in T2 than in T3 and Zn level tended to be higher in T3 than in T1. It was concluded that Mg, Se, Mn, Fe, Cu and Zn provided useful information on the pathogenesis of feline mammary tumors. Further research is needed on the tissue and serum concentrations of trace elements which may provide valuable information for the disease prognosis.

Dietary zinc deficiency or supplementation during gestation increases breast cancer susceptibility in adult female mice offspring following a J-shaped pattern and through distinct mechanisms

Zinc is required for fetal development and is involved in key processes associated with breast carcinogenesis. We evaluated whether maternal zinc deficiency or supplementation during gestation influences female offspring susceptibility to breast cancer in adulthood. C57BL/6 mice consumed during gestation control (30 p.p.m. zinc), zinc-deficient (8 p.p.m) or zinc-supplemented (45 p.p.m.) diets. Maternal zinc supplementation increased in female mice offspring the incidence of chemically-induced mammary adenocarcinomas that were heavier, compared to control group. This was accompanied by a decreased number of terminal end buds, increased cell proliferation and apoptosis, and increased tumor suppressors p21, p53 and Rassf1, Zfp382 and Stat3 expression in mammary glands, as well as increased zinc status. Although maternal zinc deficiency did not alter the incidence of these lesions, it also induced heavier mammary adenocarcinomas, compared to control group. These effects were accompanied by a decreased number of terminal end buds, increased proto-oncogenes c-Myc and Lmo4 expression and H3K9Me3 and H4K20Me3 epigenetic marks in mammary glands of offspring, and decreased zinc status and increased levels of oxidative marker malondialdehyde. The data suggest that both maternal zinc deficiency and supplementation during gestation programmed increased breast cancer susceptibility in adult mice offspring following a J-shaped pattern through distinct mechanisms.