Response to crizotinib in a patient with metastatic lung spindle cell carcinoma harboring TPM3-ROS1 fusion

Abstract

Immunohistochemical staining showed that the tumor cells were diffusely positive for pan-cytokeratin AE1/AE3, vimentin, thyroid transcription factor 1, and Ki-67 (70%) but negative for smooth muscle action, desmin, anaplastic lymphoma kinase (ALK), calretinin, melanocyte antigen, P40, P63, and Cytokeratin5/6. Tumor cells were also found in the pleural effusion [Figure 1F]. [...]the patient was diagnosed with stage IV right upper lung SpCC based on the World Health Organization criteria. In previous studies on sarcomatoid carcinoma, including SpCCs, researchers found that these patients harbored epidermal growth factor receptor (EGFR), K-ras, B-Raf proto-oncogene (Braf), HER2 (erb-b2 receptor tyrosine kinase 2), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and MET proto-oncogene (c-MET) amplifications, while EGFR mutations were rare. [4] The ROS1 gene, has a similar structure as ALK, encodes for an tyrosine receptor kinase which is involved in chromosomal translocation in lung cancer.