OBJECTIVE The purpose of this study was to explore the clinical significance of expression of Fas, CTLA-4 and RhoBTB2 genes in breast carcinoma. METHODS Semi-quantitative reverse transcriptive polymerase chain reaction (RT-PCR) was used to analyze the mRNA expression levels of the three genes in tumor tissues from 60 patients with primary breast cancer and normal breast tissues of 30 cases. The relationship between gene expression and clinicopathological factors were analyzed and determined. RESULTS The relative expression levels (gray scale ratio between target gene and internal reference gene) of Fas, CTLA-4 and RhoBTB2 genes in breast carcinoma tissues were 0.699 +/- 0.285, 1.045 +/- 0.302 and 0.625 +/- 0.160, respectively. In the normal breast tissues, they were 0.502 +/- 0.178, 0.418 +/- 0.140 and 0.843 +/- 0.218, respectively. There were statistically significant differences of the expression of those three genes between carcinoma tissues and normal breast tissues (P < 0.01). The expression level of Fas in carcinoma tissues was significantly higher in lymph node matastasis positive patients (0.782 +/- 0.313) than that in node-negative patients (0.557 +/- 0.146, P < 0.01). The expression level of CTLA-4 gene in carcinoma tissues was lower in II stage patients (0.978 +/- 0.330) than that in III stage patients (1.134 +/- 0.240, P < 0.05). The expression level of RhoBTB2 gene was lower in invasive ductal carcinoma (0.597 +/- 0.157) than that in invasive lobular carcinoma (0.717 +/- 0.145, P < 0.05). There were no correlations of expression of the three genes at mRNA level and age, ER, PR, HER2 status and survival time. Furthermore, no correlation was seen among the three genes expression (P > 0.05). CONCLUSION The expression of all the three genes at mRNA level is involved in genesis and progression of breast cancer. There exist correlations between Fas expression and axillary lymph node matastasis, CTLA-4 expression and disease stage, and RhoBTB2 expression and pathological type of breast cancer.