We found that CRP was more strongly associated with the risk of invasive breast cancer (HR for the highest quartile = 1.23, 95 % CI = 1.14–1.31) and breast cancer mortality (HR for the highest quartile = 1.46, 95 % CI = 1.07–1.97) than with in-situ breast cancer (HR for the highest quartile = 1.14, 95 % CI = 0.96–1.35). This evidence concerns the gene CRP and breast carcinoma in situ.