To investigate the expression of CD117 and DOG1 in triple-negative breast cancer (TNBC) and to explore their relationship with clinicopathologic features and prognosis.

The patients with TNBC in Peking Union Medical College Hospital from 2000 to 2011 were retrospectively collected and tissue microarrays were made. The expression of CD117 and DOG1 in tumor cells was detected by immunohistochemistry to analyze their relationship with the clinicopathological characteristics of the patients, such as age, tumor diameter, American Joint Committee on Cancer (AJCC) cancer stage, histological grade, P53, and Ki-67 proliferation index, and explore the effect of both on the survival of patients.

A total of 185 TNBC patients meeting the inclusion and exclusion criteria were selected, of which 24 (12.97%) were CD117 positive and 22 (11.89%) were DOG1 positive, with a co-expression rate of 1.62%. Compared with CD117-negative patients, CD117-positive patients had higher Ki-67 proliferation index (87.50% vs. 67.70%, P=0.048), basal-like TNBC (95.83% vs. 74.53%, P=0.020), and P53 diffuse positive (33.33% vs. 13.66%, P=0.032).Compared with DOG1-negative patients, DOG1-positive patients had lower proportions of tumor diameter ≤2 cm (22.73% vs. 45.40%, P=0.026) and basal-like TNBC (54.55% vs. 80.37%, P=0.015). The median follow-up was 71 months (range: 2-170 months), 4 cases (2.16%) were lost to follow-up, 66 cases (35.68%) relapsed or had distant metastasis, and 34 cases (18.38%) died. Survival analysis showed that AJCC stage (HR=7.624, 95% CI: 2.187-26.576, P=0.001) and CD117 positive with P53 diffuse strong positive (HR=3.942, 95% CI: 1.366-11.379, P=0.011) were negatively correlated with the overall survival of TNBC patients.

The expression of CD117 and DOG1 were significantly related to basal-like TNBC, CD117 positive with P53 diffuse strong positive may be correlated with a shorter overall survival and a higher mortality risk.