Effect of genetic strain on ovarian tumors in Tg(Amhr2-SV40TAg)1Bcv mice. Cytokeratin 19 (CK19) and α-inhibin expression in the FVB/n-Tg(Amhr2-SV40TAg)1Bcv (a) are localized to distinct regions of the tumor that appear mutually exclusive. TAg expression is found throughout the entire ovarian stroma as early as embryonic day 18 (b) with exclusion of expression from large follicles apparent at 36 and 61 days of age. Expression of TAg in the F1 ovaries from a cross of the FVB/n-Tg(Amhr2-SV40TAg)1Bcv to C57Bl/6 mice is apparent after several weeks of age and then only localized to the ovarian cortex as shown (c, day 43). Scale bars indicate 100 μM (a), 500 μM (b + c) or 100 μM (c, enlarged area).