SMAD2 and neoplasm: Next, to uncover potential effect of Smad2 deletion on ovarian tumor development at an early stage, we examined the tumor status in the Smad2flox/-; Inha-/-; Amhr2cre/+ mice at various time points between 4 and 9 weeks of age, since inhibin-deficient mice can develop tumors as early as 4 weeks.