TP53 and ductal breast carcinoma in situ: Only 2% of the non-neoplastic ducts and 18% of the ductal carcinoma in situ components showed p53 protein expression, resulting in an odds ratio of 11.96 (95% CI: 1.47-96.92), while the difference in p53 positivity between ductal carcinoma in situ and invasive ductal carcinoma gave a nonsignificant result (Table 1).