RB1 and in situ carcinoma: Although epithelial PR(A+B) was downregulated, stromal PR(A+B) and PRB were upregulated with IRS of 2.0 ± 2.0 and 2.0 ± 1.9 as well as 2.1 ± 2.3 and 3.2 ± 3.2 in the CIS (p = 0.009) and ICC groups (p < 0.001), respectively.