Resumo

CACERES, J.M et al. Mendelian analysis of resistance/susceptibility to a transplantable breast tumor in a murine model. BAG, J. basic appl. genet. [online]. 2015, vol.26, n.2, pp.83-95. ISSN 1852-6233.

Behavior of breast adenocarcinoma M-406, a type B, semi-differentiated and triple negative (ER, PR-, HER2-) transplantable tumor was studied in the F1 and F2 mice populations derived from crosses between from the inbred lines CBi (susceptible: take 100 %, 100 % lethality) and CBi- (resistant: take 100 %, 100 % regression). Reciprocal hybrids behaved both as CBi (take 100 %, 100 % lethality), revealing the absence of maternal effects. In the F2 combinations, the tumor grew exponentially in 74.9 % of the animals and was rejected in the remaining 25.1 %, a segregation compatible with the autosomal dominant condition of tumor susceptibility observed in the F1. Analysis of tumor doubling time in the various F2 combinations showed a higher growth rate of the tumor when a double genetic load of maternal CBi (susceptible) origin was present in comparison with a double maternal CBi- (resistant) load; this response was not evinced in the remaining two F2 combinations. This response was only observed in females, suggesting the existence of epigenetic phenomena associated with the sex of the tumor carrier.

Palavras-chave : Tumor growth; Tumor doubling time; Mice; Triple negative breast cancer.