Impact of Somatic Mutations in Non-Small-Cell Lung Cancer: A Retrospective Study of a Chinese Cohort

Strength of selection in lung tumors correlates with clinical features better than tumor mutation burden

Single nucleotide substitutions are the most common type of somatic mutations in cancer genome. The goal of this study was to use publicly available somatic mutation data to quantify negative and positive selection in individual lung tumors and test how strength of directional and absolute selection is associated with clinical features. The analysis found a significant variation in strength of selection (both negative and positive) among tumors, with median selection tending to be negative even though tumors with strong positive selection also exist. Strength of selection estimated as the density of missense mutations relative to the density of silent mutations showed only a weak correlation with tumor mutation burden. In the "all histology together" analysis we found that absolute strength of selection was strongly correlated with all clinically relevant features analyzed. In histology-stratified analysis selection was strongest in small cell lung cancer. Selection in adenocarcinoma was somewhat higher compared to squamous cell carcinoma. The study suggests that somatic mutation- based quantifying of directional and absolute selection in individual tumors can be a useful biomarker of tumor aggressiveness.

Treatment with Anlotinib After Chemotherapy and EGFR-TKI Resistance in Lung Adenosquamous Carcinoma with Concurrent EGFR and PIK3CA Mutations: A Case Report and Literature Review

Concurrent mutations of epidermal growth factor receptor (EGFR) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) in non-small cell lung cancer (NSCLC) are rare, and the presence of concurrent mutations may complicate treatment. Herein, we report a case of primary lung adenosquamous carcinoma with concurrent EGFR 21 (L858R) and PIK3CA (H1047R/E545K) mutations, and the results of a literature review to help management and treatment. A 49-year-old female was admitted our department for coughing and excessive sputum production for more than 1 month. Computed tomography (CT) of the chest identified a lesion, and a CT-guided needle biopsy was performed. Pathological examination and immunohistochemistry (IHC) staining confirmed a diagnosis of primary lung adenosquamous carcinoma. Amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) gene sequencing demonstrated mutations in both EGFR 21 (L858R) and PIK3CA (H1047R/E545K) mutations in adenocarcinoma (AC) component. She was treated with pemetrexed plus platinum-based chemotherapy and an EGFR-tyrosine kinase inhibitor (TKI). Disease progression occurred with gefitinib or osimertinib as maintenance therapy. A repeat CT-guided needle biopsy was performed, and generation sequencing (NGS) revealed EGFR 21 (L858R) and PIK3CA (H1047R/E545K) mutations. Anlotinib monotherapy was then administered as the third-line treatment, and there was a PR. The patient is currently still receiving treatment and follow-up. To our knowledge, there is little evidence that anlotinib is beneficial when there are concurrent EGFR and PIK3CA mutations. PIK3CA mutations are associated with poor therapeutic effects and short survival time. Concurrent EGFR and PIK3CA mutations do not respond to EGFR-TKI treatment. Chemotherapy should be given in combination with a TKI and can prolong the progression-free survival (PFS) and overall survival (OS) of patients with lung cancer.