RB1

This study characterized the genomic landscape of leiomyosarcoma, a rare and aggressive tumor, by analyzing a large dataset from the AACR Project GENIE. Researchers examined over 1,000 tumor samples, identifying the most frequent somatic mutations and copy number alterations. TP53, RB1, and ATRX were the most commonly altered genes, with homozygous deletions of RB1 and TP53, and MAP2K4 amplifications. The study also highlighted enriched IGF2 and AXIN1 alterations in metastatic samples, suggesting their potential role in disease progression. These findings enhance the understanding of leiomyosarcoma biology and could guide future precision oncology strategies.

This study investigates histologic transformation to lung squamous cell carcinoma (LUSC) in EGFR-mutant lung adenocarcinoma (LUAD) patients, an underrecognized resistance mechanism. Multiomic analyses revealed that patients with transforming or adenosquamous (LUAS) phenotypes experienced shorter overall survival on first-line osimertinib. Inactivation of the retinoblastoma (Rb) pathway, particularly via CDKN2A/B deletions, was identified as a key driver of this transformation. Furthermore, MET pathway upregulation was observed, and combined EGFR and MET inhibition demonstrated efficacy in preclinical models. These findings suggest novel strategies to counteract this aggressive form of resistance.

This retrospective study investigated the frequency and molecular profiles of PAX8-positive conventional urothelial carcinomas (UCs) of the urinary bladder. Out of 101 cases, 10% were found to be PAX8-positive by immunohistochemistry. Next-generation sequencing (NGS) was performed on 20 cases, including all PAX8-positive UCs. The findings revealed that PAX8-positive UCs frequently harbored TERT promoter mutations, TSC1 alterations, NOTCH1 loss, and WT1 loss, while notably lacking RB1 loss, distinguishing them from PAX8-negative UCs. These results indicate a distinct molecular signature for PAX8-positive UCs, emphasizing the need for careful diagnostic interpretation of PAX8.

This retrospective study investigated the incidence of MYCN amplification in unilateral retinoblastoma and its association with RB1 inactivation and clinical features. Out of 139 analyzed cases, 7.2% exhibited MYCN amplification, and all these cases also showed RB1 inactivation. Researchers found that MYCN amplification was significantly associated with more advanced disease and aggressive histopathological features, including secondary glaucoma and massive choroidal or scleral invasion. These findings suggest that MYCN amplification could identify a more aggressive subgroup of retinoblastomas.