Objective:To investigate the clinicopathological characteristics and molecular genetic alterations of cervical embryonal rhabdomyosarcoma (ERMS).Methods:Three cases of cervical ERMS diagnosed at Peking University Third Hospital from April 2017 to April 2023 were retrospectively analyzed. Clinicopathological data, molecular genetics, treatments, and follow-up information were examined.Results:Three patients with cervical ERMS, aged 17, 15, and 23 years, respectively, were included. All presented with polypoid masses at the vaginal opening. Histologically, oval or short-fusiform tumor cells in myxedematous stroma were arranged in dense and sparse regions, accompanied by various degrees of rhabdomyoblastic differentiation. Immunohistochemically, MyoD1, Myogenin and Myoglobin were expressed in all 3 tumors. The DICER1 gene mutation was detected in all 3 tumors, while the DICER1 germline mutation was detected only in 2 cases. All patients received local resection and adjuvant chemotherapies. The follow-up period was 10-76 months. One patient experienced local recurrence, and two remained disease-free.Conclusions:Cervical ERMS predominantly affects young females and commonly presents as a prolapsed polypoid cervical lesion. It demonstrates distinctive molecular genetic characteristics, most frequently DICER1 mutations, and shows a strong association with the DICER1 syndrome.

Objective:To investigate the clinical values of fluorescent PCR-capillary electrophoresis (PCR/CE) for detecting somatic mutations in the proofreading exonuclease domain of DNA polymerase epsilon (POLE-exo*) in endometrial carcinomas (EC), as compared with Sanger sequencing.Methods:A total of 280 EC cases diagnosed at the Department of Pathology at Peking University Third Hospital, Beijing, China from December 2022 to December 2023 were collected. Ten cases, which had previously been confirmed to harbor POLE pathogenic mutations through next-generation sequencing (NGS), were excluded. Subsequently, parallel sequencing using both PCR/CE and Sanger sequencing methods was conducted on the remaining 270 EC samples without prior POLE testing, aiming to examine 11 known pathogenic mutation-sites located within exons 9, 11, 13, and 14 of the POLE gene. NGS was then carried out on the EC cases in which the PCR/CE and/or Sanger sequencing results indicated the presence of POLE-exo*.Results:Among the 270 EC samples, POLE-exo* was detected in 4 cases (4/270, 1.5%) using Sanger sequencing. In contrast, the PCR/CE identified POLE-exo* in 12 cases (12/270, 4.4%). It was noteworthy that all cases in which POLE-exo* was detected through Sanger sequencing were also successfully identified using PCR/CE (4/4, with a detection rate of 100%). These results were further verified by NGS. The PCR/CE also uncovered an additional 8 cases (8/266, 3.0%) of POLE-exo* in the 266 samples that were negative for POLE mutations per Sanger sequencing. Of these 8 cases, 4 were validated using NGS, exhibiting variant allele frequency (VAF) below 10%, but tumor mutation burdens exceeding 10 mutations per megabase. However, due to small tumor sizes, NGS verification could not be performed on the remaining 4 PCR/CE-positive but Sanger-negative cases.Conclusion:The PCR/CE exhibits better sensitivity and detection capabilities than the Sanger sequencing in identifying POLE-exo* in EC samples, particularly in detecting low VAF.

Objective:To investigate the clinicopathological characteristics and molecular genetic alterations of cervical embryonal rhabdomyosarcoma (ERMS).Methods:Three cases of cervical ERMS diagnosed at Peking University Third Hospital from April 2017 to April 2023 were retrospectively analyzed. Clinicopathological data, molecular genetics, treatments, and follow-up information were examined.Results:Three patients with cervical ERMS, aged 17, 15, and 23 years, respectively, were included. All presented with polypoid masses at the vaginal opening. Histologically, oval or short-fusiform tumor cells in myxedematous stroma were arranged in dense and sparse regions, accompanied by various degrees of rhabdomyoblastic differentiation. Immunohistochemically, MyoD1, Myogenin and Myoglobin were expressed in all 3 tumors. The DICER1 gene mutation was detected in all 3 tumors, while the DICER1 germline mutation was detected only in 2 cases. All patients received local resection and adjuvant chemotherapies. The follow-up period was 10-76 months. One patient experienced local recurrence, and two remained disease-free.Conclusions:Cervical ERMS predominantly affects young females and commonly presents as a prolapsed polypoid cervical lesion. It demonstrates distinctive molecular genetic characteristics, most frequently DICER1 mutations, and shows a strong association with the DICER1 syndrome.

Objective:To investigate the clinical values of fluorescent PCR-capillary electrophoresis (PCR/CE) for detecting somatic mutations in the proofreading exonuclease domain of DNA polymerase epsilon (POLE-exo*) in endometrial carcinomas (EC), as compared with Sanger sequencing.Methods:A total of 280 EC cases diagnosed at the Department of Pathology at Peking University Third Hospital, Beijing, China from December 2022 to December 2023 were collected. Ten cases, which had previously been confirmed to harbor POLE pathogenic mutations through next-generation sequencing (NGS), were excluded. Subsequently, parallel sequencing using both PCR/CE and Sanger sequencing methods was conducted on the remaining 270 EC samples without prior POLE testing, aiming to examine 11 known pathogenic mutation-sites located within exons 9, 11, 13, and 14 of the POLE gene. NGS was then carried out on the EC cases in which the PCR/CE and/or Sanger sequencing results indicated the presence of POLE-exo*.Results:Among the 270 EC samples, POLE-exo* was detected in 4 cases (4/270, 1.5%) using Sanger sequencing. In contrast, the PCR/CE identified POLE-exo* in 12 cases (12/270, 4.4%). It was noteworthy that all cases in which POLE-exo* was detected through Sanger sequencing were also successfully identified using PCR/CE (4/4, with a detection rate of 100%). These results were further verified by NGS. The PCR/CE also uncovered an additional 8 cases (8/266, 3.0%) of POLE-exo* in the 266 samples that were negative for POLE mutations per Sanger sequencing. Of these 8 cases, 4 were validated using NGS, exhibiting variant allele frequency (VAF) below 10%, but tumor mutation burdens exceeding 10 mutations per megabase. However, due to small tumor sizes, NGS verification could not be performed on the remaining 4 PCR/CE-positive but Sanger-negative cases.Conclusion:The PCR/CE exhibits better sensitivity and detection capabilities than the Sanger sequencing in identifying POLE-exo* in EC samples, particularly in detecting low VAF.

Epithelial ovarian cancer (EOC) is one of the leading causes of death from gynecologic cancers and peritoneal dissemination is the major cause of death in patients with EOC. Although the loss of 4.1N is associated with increased risk of malignancy, its association with EOC remains unclear. To explore the underlying mechanism of the loss of 4.1N in constitutive activation of epithelial-mesenchymal transition (EMT) and matrix-detached cell death resistance, we investigated samples from 268 formalin-fixed EOC tissues and performed various in vitro and in vivo assays. We report that the loss of 4.1N correlated with progress in clinical stage, as well as poor survival in EOC patients. The loss of 4.1N induces EMT in adherent EOC cells and its expression inhibits anoikis resistance and EMT by directly binding and accelerating the degradation of 14-3-3 in suspension EOC cells. Furthermore, the loss of 4.1N could increase the rate of entosis, which aggravates cell death resistance in suspension EOC cells. Moreover, xenograft tumors in nude mice also show that the loss of 4.1N can aggravate peritoneal dissemination of EOC cells. Single-agent and combination therapy with a ROCK inhibitor and a 14-3-3 antagonist can reduce tumor spread to varying degrees. Our results not only define the vital role of 4.1N loss in inducing EMT, anoikis resistance, and entosis-induced cell death resistance in EOC, but also suggest that individual or combined application of 4.1N, 14-3-3 antagonists, and entosis inhibitors may be a promising therapeutic approach for the treatment of EOC.