# First Report of Entrectinib as a Treatment Option for Pure Squamous Cell Carcinoma Harboring ROS1 Rearrangement: Exploring the Role of Next-Generation Sequencing in Targeted Therapy

## TL;DR

A rare case of squamous cell lung cancer with a ROS1 gene rearrangement was successfully treated with entrectinib, emphasizing the value of next-generation sequencing in identifying treatable mutations.

## Contribution

This is the first reported case of ROS1-rearranged pure squamous cell carcinoma successfully treated with entrectinib.

## Key findings

- ROS1 rearrangement was identified in a pure squamous cell carcinoma case using next-generation sequencing.
- Entrectinib treatment led to a positive clinical response in the patient for approximately one year.
- The case suggests that ROS1 could be a viable therapeutic target in squamous cell carcinoma, despite its rarity.

## Abstract

Lung cancer remains the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for the majority of cases. Among the NSCLC subtypes, squamous cell carcinoma (SCC) is less frequently associated with actionable genetic alterations. Herein, we present the first known case of ROS1 rearrangement in pure SCC, identified using next-generation sequencing (NGS), and successfully treated with entrectinib for approximately one year. This case highlights the potential of ROS1 as a therapeutic target in SCC, which has historically been considered rare, as ROS1-rearranged SCC accounts for only 0.2% according to the Foundation Medicine database. This underscores the importance of incorporating NGS into clinical practice, particularly for never smokers/light smokers or patients with advanced SCC of the lungs, to identify targetable mutations and guide personalized therapy.