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Ras-related GTP binding (Rag) GTPases are required to activate mechanistic target of rapamycin complex 1 (mTORC1), which plays a central role in cell growth and metabolism and is considered as one of the most important oncogenic pathways. Therefore, Rag GTPases have been speculated to play a pro-cancer role via mTOR induction. However, aside from stimulation of mTOR signaling, firm links connecting Rag GTPase activity and their downstream effectors with cancer progression, remain largely unreported. In this study, we reported a novel link between RagB/C and a known oncoprotein phosphatase of regenerating liver-3 (PRL-3) by screening 22 pairs of tumors and their adjacent normal tissues from gastric, liver and lung cancers, and validating our findings in cancer cell lines with ectopic RagB/C expression. RagB/C was found to enhance PRL-3 stability by modulating two major cellular protein degradation pathways: lysosomal-autophagy and ubiquitin-proteasome system (UPS). Functionally, we identified the correlation between RagB/C expression with poor clinical outcomes in breast or colon cancer patients who also showed low PRL-3 mRNA expression from data retrieved from TCGA datasets, highlighting the potential relevance of Rag GTPase and PRL-3 mRNA in combination as a prognostic clinical biomarker. • RagB/C is upregulated in tumor tissues and correlates with PRL-3 expression. • RagB/C promotes PRL-3 stability, rather than enhances PRL-3 protein synthesis. • RagB/C inhibits both autophagy and ubiquitin-proteasome degradation of PRL-3. • Novel lysosomal localization and ubiquitination of PRL-3 has been identified. • RagB/C correlates with poor survival in cancer patients expressing low PRL-3 mRNA. [ABSTRACT FROM AUTHOR]

Clear cell endometrial carcinoma represents an uncommon and poorly understood entity. Data from molecular/genomic profiling highlighted the importance of various signatures in assessing the prognosis of endometrial cancer according to four classes of risk (POLE mutated, MMRd, NSMP, and p53 abnormal). Unfortunately, data specific to clear cell histological subtype endometrial cancer are lacking. More recently, data has emerged to suggest that most of the patients (more than 80%) with clear cell endometrial carcinoma are characterized by p53 abnormality or NSMP type. This classification has important therapeutic implications. Although it is an uncommon entity, clear cell endometrial cancer patients with POLE mutation seem characterized by a good prognosis. Chemotherapy is effective in patients with NSMP (especially in stage III and IV) and patients with p53 abnormal disease (all stages). While, preliminary data suggested that patients with MMRd are less likely to benefit from chemotherapy. The latter group appears to benefit much more from immune checkpoint inhibitors: recent data from clinical trials on pembrolizumab plus lenvatinib and nivolumab plus cabozantinib supported that immunotherapy plus tyrosine kinase inhibitors (TKI) would be the most appropriate treatment for recurrent non-endometrioid endometrial cancer (including clear cell carcinoma) after the failure of platinum-based chemotherapy. Moreover, ongoing clinical trials testing the anti-tumor activity of innovative products will clarify the better strategies for advanced/recurrent clear cell endometrial carcinoma. Further prospective evidence is urgently needed to better characterize clear cell endometrial carcinoma. • Clear cell endometrial cancer represents uncommon uterine tumor. • Multi-modal treatment should be considered in patient with clear cell endometrial cancer. • Immunotherapy might play a role in patients with MMRd clear cell endometrial cancer. • ATr , PIK3CA , DDR , and HER2 might be potential targets in clear cell endometrial cancer [ABSTRACT FROM AUTHOR]

Serous endometrial cancer represents a relative rare entity accounting for about 10% of all diagnosed endometrial cancer, but it is responsible for 40% of endometrial cancer-related deaths. Patients with serous endometrial cancer are often diagnosed at earlier disease stage, but remain at higher risk of recurrence and poorer prognosis when compared stage-for-stage with endometrioid subtype endometrial cancer. Serous endometrial cancers are characterized by marked nuclear atypia and abnormal p53 staining in immunohistochemistry. The mainstay of treatment for newly diagnosed serous endometrial cancer includes a multi-modal therapy with surgery, chemotherapy and/or radiotherapy. Unfortunately, despite these efforts, survival outcomes still remain poor. Recently, The Cancer Genome Atlas (TCGA) Research Network classified all endometrial cancer types into four categories, of which, serous endometrial cancer mostly is found within the "copy number high" group. This group is characterized by the increased cell cycle deregulation (e.g., CCNE1 , MYC, PPP2R1A , PIKCA, ERBB2 and CDKN2A) and TP53 mutations (90%). To date, the combination of pembrolizumab and lenvatinib is an effective treatment modality in second-line therapy, with a response rate of 50% in advanced/recurrent serous endometrial cancer. Owing to the unfavorable outcomes of serous endometrial cancer, clinical trials are a priority. At present, ongoing studies are testing novel combinations of various targeted and immunotherapeutic agents in newly diagnosed and advanced/recurrent endometrial cancer - an important strategy for serous endometrial cancer, whereby tumors are usually p53+ and pMMR, making response to PD-1 inhibitor monotherapy unlikely. Here, the rare tumor working group (including members from the European Society of Gynecologic Oncology (ESGO), Gynecologic Cancer Intergroup (GCIG), and Japanese Gynecologic Oncology Group (JGOG)), performed a narrative review reporting on the current landscape of serous endometrial cancer and focusing on standard and emerging therapeutic options for patients affected by this difficult disease. • Uterine serous carcinoma (USC) is a rare and aggressive variant of endometrial cancer. • USCs are generally mismatch repair proficient and have extensive copy number alterations. • Multi-modal treatment including surgery, chemotherapy and/or radiotherapy should be considered in the majority patient with USC. • Novel combinations of immune checkpoint inhibitors with targeted therapies are under evaluation. [ABSTRACT FROM AUTHOR]