Identification of a novel PRR15L-RSPO2 fusion transcript in a sigmoid colon cancer derived from superficially serrated adenoma

AbstractSuperficially serrated adenoma (SuSA) is a recently proposed subtype of colorectal serrated lesion. We here report a sigmoid colon cancer derived from SuSA, which exhibited aggressive clinical behavior. Endoscopically, the tumor appeared as a superficial elevated lesion with a large nodule. Histological examination of the surgically resected material showed tubular adenocarcinoma associated with SuSA. Although tumor invasion was limited to the submucosal layer, lymph node and extranodal metastases were detected. The patient subsequently developed peritoneal metastases and died 15  months after surgery. Molecular analyses identified aKRAS mutation and a novelPRR15L-RSPO2 fusion, which retains the entire coding region ofRSPO2, in both SuSA and adenocarcinoma components. The present study demonstrates the malignant potential of SuSA and expands the spectrum ofRSPO fusions in colorectal neoplasms.
Source: Virchows Archiv - Category: Pathology Source Type: research