Clinicopathologic And Biological Features Of Triple Negative Breast Cancer And Their Prognostic Significance

Objective: To analyze clinical and pathological features and to observe prognostic factors in triple negative breast cancer (TNBC) . Furthermore, to investigate the expression of EGFR,E-cadherin and AR in TNBC and non-TNBC and to evaluate its significance.Methods: Based on ER, PR and Her-2 status determined using immunohistochemistry, 509 cases of breast cancer were grouped as TNBC and non-TNBC. Clinicopathologic features between two groups were compared. 5-year disease-free survival (DFS) was analyzed by Kaplan-Meier Method. Univariate regression and Cox multivariate regression were preformed to analyze association between prognosis and cliniopathologic features. 50 cases from each group were collected. Expression of EGFR, E-cadherin and AR by immunohistochemistry and its significance was analyzed.Results:21.4% of cases (109/509) were TNBC and the majority of pathologic type was infiltrative ductal carcinoma. TNBC had higher incidence rates than non-TNBC in medullarly type and grade III tumor (P<0.05) . No significance was found in other clinicopatholgic feature between two groups. The rate of local recurrence or distant metastasis in TNBC was higher than non-TNBC (P < 0.05) . 5-year DFS in TNBC was lower than in non-TNBC(Log rank=4.661, P=0.031) . Univariate regression analysis suggested that tumor size (P=0.000), TNM stage (P=0.000) , and lymph nodes status (P=0.000) were prognostic factors in TNBC (P=0.000). Age (≥50 or < 50),menopausal status,histological grade,family history were not significant prognostic factors. Cox multivariate analysis demonstrated that the status of lymph nodes was an independent prognostic factor (HR= 2.999, 95% CI: 2.061～4.358, P=0.000) .The positive rates of EGFR and AR in 100 case of breast cancer were 44% (44/100) and 49 %(49/100) respectively. The aberrant expression of E-cadherin was 62 %(62/100). In positive axillary lymph nodes group, EGFR positivity and aberrant expression of E-cadherin were higher than that in negative lymph nodes group, while AR positivity was lower than that in negative lymph nodes group. The expression ofthree biomarkers were not associated with age, menopausal status, TNM stage andtumor size (P>0.05) . In recurrence or metastasis group, EGFR positivity andaberrant expression of E-cadherin were higher than in non- recurrence or metastasisgroup, while AR positivity was lower than that in non- recurrence or metastasis group(P<0.05) . 5-year DFS in EGFR positive group was lower than in EGFR negativegroup while 5-year DFS in E-cadherin normal group and AR positive group werehigher than in E-cadherin aberrant group and AR negative group respectively(P<0.05) .In TNBC, EGFR positivity and aberrant expression of E-cadherin were higher than in non-TNBC, while AR positivity was lower than in non-TNBC (P<0.05) . In positive axillary lymph nodes group, EGFR positivity and aberrant expression of E-cadherin were higher than that in negative lymph nodes group, while AR positivity was lower than that in negative lymph nodes group. EGFR positivity was associated with recurrence or metastasis. 5-year DFS in EGFR positive group was lower than in EGFR negative group; However, expression of E-adhering and AR was not correlated with recurrence or metastasis and prognosis.Conclusions:TNBC was a special subtype of breast cancer and the majority of pathologic type was infiltrative ductal carcinoma .The rate of medullary type and grade III was higher than that in non-TNBC. TNBC had a tendency of local relapse or distant metastasis and had poor prognosis. Tumor size, TNM stage and lymph nodes status were prognostic factors. Lymph nodes status was an independent prognostic factor.Of TNBC, expression of EGFR was associated with positive axillary lymph nodes, recurrence and metastasis and poor prognosis. Aberrent expression of E-cadherin were associated with positive axillary lymph nodes, while expression of AR was inversely correlated .Expression of E-cadherin and AR were not associated with prognosis, recurrence or metastasis. EGFR can be applied to predict prognosis and be a molecular target in TNBC.