Association of High LDH and Low Glucose Levels in Pleural Space with HER2 Expression in Non-Small Cell Lung Cancer

Background: Evidence shows direct link of HER2 to increased glycolysis and over production of lactatedehydrogenase (LDH). HER2 overexpression, high LDH and low glucose pleural levels are associated withpoor prognosis in lung cancer. Here, their relationships were investigated. Materials and
Methods: HER2positivity was studied using immunohistochemistry in non-small cell lung cancer. Glucose and LDH levels weremeasured using commercial colorimetric kits.
Results: Of 42 patients (29 adenocarcinoma and 13 squamouscell carcinoma), 28 (66.7%) were HER2-negative, 14 (33.3%) were HER2- positive, including 9 (21.4%) weaklystained (1+) and 5 (11.9%) moderately stained (2+) samples. The relationship between HER2 and glucose andLDH levels were tested in 20 newly diagnosed lung cancer patients who had simultaneous pleural and serumsamples. Pleural and serum LDH levels were increased, and pleural glucose levels were decreased with thescale of HER2 positivity, and that the difference in glucose levels between HER2-negative group and HER2-positive patients scored at 2+ reached statistical significance (p=0.02). This latter group all had pleural glucoselevels below 40 mg/dl.
Conclusions: For the first time, we showed a significant association between low pleuralglucose level and overexpression of HER2 in lung cancer. Further investigations are warranted to disclose theassociation of HER2 with low pleural glucose levels in other populations, with a larger sample size, in malignantpleural effusions caused by other types of cancer, and finally to assess employment as a screening tool for findingHER2-positive cases of lung cancer.