Correlation of CD8+ Expression, Foxp3+ Expression, and CD8+/Foxp3+ Ratio with Triple Negative Breast Cancer Stage in Sanglah General Hospital

BACKGROUND: Triple negative breast cancer (TNBC) is a breast cancer sub-type that lacks ER, PR and HER-2 expression. This type tends to be more aggressive than other types of breast cancer, with poor prognosis, distant metastases, higher recurrence rate, and lower overall survival. The TNBC is resistant to hormonal therapy, but generally very susceptible to chemotherapy. Expression of CD8+ and Foxp3+ were parts of the TIL, which often found in TNBC as an immune response to tumour antigens following antigens presenting cell (APC) stimulation. AIM: This study was conducted to find out whether the expression of CD8+, Foxp3+ and CD8+/Foxp3+ ratio was associated with the stage of TNBC. METHODS: This cross-sectional study was conducted from January 2014 until December 2016 at Sanglah Hospital with 46 research subjects. Two paraffin blocks were prepared for each sample to examine the CD8+ expression and Foxp3+ expression. Data were analysed using the Chi-Square test or Fisher’s Exact tests as an alternative for bivariate analysis and logistic regression for multivariate analysis. RESULTS: On bivariate analysis, we found a low of CD8+ expression in advanced stage (p < 0.001 with OR 3.5; CI 1.611-7.727). Expression Foxp3+ in advanced stage (p = 0.482; OR 0.8; CI 0.497-1.374), while the ratio of CD8+/Foxp3+ (p = 0.213; OR 2.2; CI 0.650-7.132). On multivariate analysis, a low of CD8+ expression (adjusted OR 16.5; CI 3.735-7.370; p < 0.001) was obtained. CONCLUSION: Low expression of CD8+ was associated with the advanced stage of TNBC. The risk of becoming an advanced stage in TNBC patients with low CD8+ expression was 16.5 times higher than those with high of CD8+ expression. High expression of Foxp3+ was not associated with an advanced stage of TNBC. The low CD8+/Foxp3+ ratio was not associated with the advanced stage of TNBC.