Epigenetic alteration of tumor suppressor genes by promoter hypermethylation has played a key role in tumorigenesis, which is an important mechanism as indispensable as gene deletion and mutation. LRRC3B is a potential tumor suppressor gene newly discovered; however, the specific biologic function is still unknown. In the present study, we tested the expression levels of LRRC3B by methods associated with immunohistochemistry, Real-Time PCR, and methylation-specific polymerase chain reaction. Results showed that the expression levels were significantly low irrespective of methylation status, suggesting that there were other factors involved in this process. However, the expression profile of LRRC3B had a significant relationship with tissue grade, irrespective of the expressions of PR, CERB-2, VEGF, and Ki67 except in cases of p53 and ER, leading us to a conclusion that the abnormal expression of LRRC3B could serve as a useful marker for diagnosis and prognosis in breast carcinomas.