Unexpected elevation of β-hCG in EGFR-mutant lung adenocarcinoma: a case study and implications for clinical practice

Beta-human chorionic gonadotropin (β-hCG) is frequently overexpressed in germ cell and trophoblastic tumors as well as various solid tumors; however, the presence of high levels of serum β-hCG is very rare in patients with non-small cell lung cancer. This report serves as a case study of an 84-year-old, non-smoking female who was diagnosed with advanced lung adenocarcinoma with bone and pleural metastases. The serum and pleural fluid β-hCG levels were significantly increased (2,618 mIU/ml and > 10,000 mIU/ml, respectively). Next-generation sequencing of the cancerous lung tissue revealed a mutation in the epidermal growth factor receptor (EGFR) gene, consistent with a deletion of exon 19. The patient was treated with gefitinib, an EGFR tyrosine kinase inhibitor, which resulted in a partial response. Unfortunately, during treatment, the patient developed interstitial lung disease and a pulmonary infection. Despite receiving treatment with steroids and antibiotics, the condition worsened, and the patient ultimately succumbed to the illness and passed away. The overall survival was 77 days. This is the first report of pulmonary adenocarcinoma with both high serum β-hCG levels and an EGFR mutation.