SH3GLB2 and ductal breast carcinoma in situ: Next, we used immunohistochemical analysis to determine the RRIG1 expression in breast tissue specimens and found that RRIG1 was expressed in 14 of 15 normal mammary glands, 8 of 9 cases of atypical hyperplasia of the mammary gland, 6 of 10 ductal carcinoma in situ tissues, and 50 of 77 invasive breast cancer tissues (P = 0.023 between normal and invasive cancer by Fisher exact test) (Figure 1).