Clinicopathological characteristics and prognosis of different molecular types of breast cancer

Abstract

To investigate the clinicopathological characteristics of 4 subtypes of breast cancer, Luminal A, Luminal B, human epidermal growth factor receptor 2(HER2), triple-negative and their associated prognostic factors. The clinical characteristics and prognosis of 102 patients with breast cancer who treated in Wuhan University Renmin Hospital from January 2011 to November 2012 were retrospectively analyzed. The proportion of each subtype was Luminal A 27.5%, Luminal B 35.3%, HER2 14.7%, and triple-negative 22.5%. The age range was from 22 to 75 years old, with median age of 48.0 years old. All patients underwent surgery and 98 cases were also treated with chemotherapy/endocrine+ Herceptin therapy (96.1%)after surgery. The tumor size, histological grade, and lymph node metastasis had significant difference in different subtypes of breast cancer (P<0.05). Further analysis showed the proportion of HER2 tumor≤2 cm (4, 26.7%)had a tendency of smaller than that in luminal A(20, 71.4%) or triple negative(16, 69.6%) (P=0.009>0.008, P=0.019>0.008). Histological Ⅲ grade proportion in patients with HER2 subtype (8, 53.3%) was in greater tendency than that with Luminal A subtype(23, 82.1%) (P=0.039>0.008). The proportion of patients with no metastatic lymph nodes in triple negative subtype(7, 30.4%) had a tendency of smaller than that in HER2 subtype(7, 46.7%) or Luminal B subtype(17, 47.2%)(P=0.019>0.008, P=0.016>0.008). There were no significant differences in age of onset, menstruation status, operation, family cancer history, and the risk of recurrence and metastasis in different subtypes (P>0.05). In Luminal A subtype, three-years overall survival rate was 100%, and one-, two-, three-year event-free survival rate were all 92.9%. In Luminal B subtype, three-year overall survival rate was 100%, event-free survival rate at one-, two- and three-year were all 97.2%. In HER2 subtype, three-year overall survival rate was 100%, one-, two- and three-year event-free survival rate were 100%, 100%, and 93.3%, respectively. The 1, 2, 3 years overall survival rate of triple-negative subtype were 100%, 95.7%, and 95.7%, respectively. One-, two- and three-year event-free survival rate of triple-negative subtype were 95.7%, 91.3%, and 90.0% respectively. Whether triple negative subtype, recurrence risk, age of onset, menstrual status, tumor size, histological grade, lymph node metastasis, surgery, breast cancer or other family history of cancer were not significantly related with three-year event-free survival rate (P>0.05). Luminal subtype had the largest proportion and better prognosis. The proportion of tumor >2 cm and histological grade Ⅲ in patients with HER2 subtype was larger, and three-year event-free survival rate of this patients was lower. Triple-negative subtype had a greater tendency of lymph node metastasis and the lowest three-year event-free survival. Tumor size, histological grade and lymph node metastasis may be the important factors for the prognosis of breast cancer.