Association of lactate dehydrogenase levels of pleural effusion in human with epidermal growth factor receptor 2 status in pleural metastatic breast cancer

Overexpression of the Human Epidermal Growth Factor Receptor (HER2) gene will increase the expression of Lactate Dehydrogenase (LDH) causing increased HSF-1, resulting in an increase in the glycolysis process, increasing cancer cell proliferation and apoptotic disorders. This study aimed to determine the relationship between pleural fluid LDH levels and HER2 status in breast cancer patients. This was a study with a cross-sectional study design on 35 breast cancer patients with complaints of pleural effusion that had been performed thoracentesis and pleural effusion fluid examination. The results of the statistical test with Chi-Square with a 95% significance level obtained p = 0.004. Statistically, it can be said there was a significant relationship between LDH levels of pleural effusion fluid and HER2 status. The results of the calculation of the odds ratio (OR) obtained OR = 42 and CI = 95% (4.351 – 405.402). It can be interpreted that HER2 status would positively increase the LDH level of pleural effusion fluid by 42x compared with the negative HER2 status. Correlation between HER2 status and LDH level of pleural effusion fluid was considered as positively strong (Chi-Square Contingency Coefficient = 0.56). LDH fluid levels of pleural effusion can be done to predict HER2 status of patients in patients with pleural metastatic breast cancer.