Histological transformation of non-small cell lung cancer: Clinical analysis of nine cases

Core Tip

Core Tip: We retrospectively diagnosed nine cases of non-small cell lung cancer (SCLC) transforming to SCLC, large-cell neuroendocrine carcinoma, or squamous cell carcinoma on re-biopsy after epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). Tumor re-biopsy should be performed routinely when EGFR-TKI therapy fails in lung cancer patients to avoid ignoring histological transformation and to select a subsequent therapeutic strategy. The plasma pro-gastrin-releasing peptide and NSE levels could be valuable and significant biomarkers to predict histological transformation. The transformed tumor retained the original EGFR mutation, which indicates that histological transformation represents an evolution from the initial tumor.