GNAS

This study re-evaluates the clinicopathological and molecular features of nonampullary duodenal neoplasms with gastric phenotype, proposing a novel classification. Analyzing 105 lesions, researchers observed a predominance of low-grade tumors and frequent heterogeneity. Next-generation sequencing revealed recurrent mutations in GNAS, KRAS, and APC. MDM2 gene amplification was identified as a potential marker for histological progression in high-grade tumors. Despite morphological diversity, the prognosis was extremely favorable, with no metastases, supporting the reclassification as "gastric-type adenomas."

This study analyzed the genomic profile of 480 patients with metastatic adenocarcinoma of unknown primary (ACUP) using the FoundationOne CDx platform. The most frequent mutations included TP53, KRAS, and CDKN2A. Results showed that GNAS and PIK3CA mutations were associated with better overall survival. Conversely, ARID1A and NOTCH1 alterations were linked to a worse prognosis. These findings highlight the significance of specific genomic alterations as prognostic markers in ACUP.