Squamous Cell Lung Carcinoma with ROS1CD74-ROS1 Fusion 76% Rearrangement and PDL-1 50% TPS: A Case Report

In the Philippines, lung cancer is the 4th most frequent cancer among women. Adenocarcinoma is the predominant histology type among females, worldwide. Squamous cell lung carcinoma is most associated with familial clustering of cancer, particularly among women. ROS1 rearrangements are extremely rare in squamous cell lung carcinoma (less than 0.2% of cases). Squamous cell lung cancer typically has higher PD-L1 expression than adenocarcinoma. Most ROS1-positive tumors do not express PD-L1 and have a low tumor mutational burden. The correlation between ROS1 rearrangements and PD-L1 overexpression is the least investigated among the druggable translocations in NSCLC. Here is presented a 69-year-old female, nonsmoker with poorly differentiated squamous cell lung carcinoma presenting a massive right upper lung mass adherent to the middle mediastinal structures, with pleural effusion, with ROS1CD74-ROS1 fusion 76% rearrangement and PDL-1 50% TPS, with several co-morbidities and a strong family history of cancer.