Prognostic impact of combined progression index based on peritoneal grading regression score and peritoneal cytology in peritoneal metastasis.

AIMS: The peritoneal regression grading score (PRGS) and peritoneal cytology (PC) assess response to chemotherapy in peritoneal metastasis (PM) in a setting of palliative treatment by pressurized intraperitoneal aerosol chemotherapy (PIPAC). Progression has been defined as an increase of PRGS between first and third PIPAC procedures (iPRGS). iPRGSand positive peritoneal cytology were not associated with prognostic impact. These results may be explained by a lack of statistical power. Also, it is not known whether the mean or the highest PRGS among taken peritoneal biopsies bears the highest clinical value. We therefore conducted the largest prospective study to investigate the prognostic impact of PGRS, PC, and their combination, designated as combined progression index (CPI). METHODS AND RESULTS: Patients with PM who underwent >3 PIPAC (n = 112) between December 2016 and February 2019 were prospectively included. A significant difference in OS and PFS according to CPI (used highest value of PRGS) was found (OS: CPI-, 83.3, 95% CI [49.8; NA] vs. CPI+, 48.1, 95% CI [38.5; 66.4] months; and PFS (respectively, 59.7, 95% CI [43.0; 96.0] vs. 33.7, 95% CI [30.4; 44.2] months). PRGS or PC had no independent prognostic impact. CPI+ was an independent predictor of worse prognosis, in OS (HR = 5.24, 95% CI [2.07; 13.26]), and PFS (HR = 4.41, 95% CI [1.40; 13.88]). CONCLUSIONS: The CPI based on highest PRGS and PC was found to be independently associated with a worse prognosis for OS and for PFS in the setting of peritoneal metastasis. These results indicate that it should be of interest to systematically take peritoneal fluid for cytological examination and to implement the CPI in the therapeutic decision-making process in the context of PIPAC.

ß-Catenin nuclear expression discriminates deep penetrating nevi from other cutaneous melanocytic tumors.

Recent advances in genomics have improved the molecular classification of cutaneous melanocytic tumors. Among them, deep penetrating nevi (DPN) and plexiform nevi have been linked to joint activation of the MAP kinase and dysregulation of the ß-catenin pathways. Immunohistochemical studies have confirmed cytoplasmic and nuclear expression of ß-catenin and its downstream effector cyclin D1 in these tumors. We assessed nuclear ß-catenin immunohistochemical expression in a large group of DPN as well as in the four most frequent differential diagnoses of DPN: "blue" melanocytic tumors, Spitz tumors, nevoid and SSM melanomas, and pigmented epithelioid melanocytomas (PEM). Nuclear ß-catenin expression was positive in 98/100 DPN and 2/16 of melanomas (one SSM and one nevoid melanoma with a plexiform clone) and was negative in all 30 Spitz, 26 blue, and 6 PEM lesions. In 41% DPN, ß-catenin expression was positive in more than 30% nuclei. No differences were observed in cytoplasmic and nuclear cyclin D1 expression between these tumor groups, suggesting alternate, ß-catenin-independent, activation pathways. We have subsequently studied nuclear ß-catenin expression in a set of 13 tumors with an ambiguous diagnosis, for which DPN was part of the differential diagnosis. The three out of four patients showing canonical DPN mutation profiles were the only ß-catenin-positive cases. We conclude that nuclear ß-catenin expression, independently from CCND1 expression, in a dermal melanocytic tumor is an argument for its classification as DPN. In ambiguous cases and in early combined DPN lesions, this antibody can be helpful as a screening tool. ß-Catenin is also potentially expressed in a subset of malignant melanomas with CTNNB1 mutations.

Role of epithelial-mesenchymal transition factors in the histogenesis of uterine carcinomas.

Several subtypes of high-grade endometrial carcinomas (ECs) contain an undifferentiated component of non-epithelial morphology, including undifferentiated and dedifferentiated carcinomas and carcinosarcomas (CSs). The mechanism by which an EC undergoes dedifferentiation has been the subject of much debate. The epithelial-mesenchymal transition (EMT) is one of the mechanisms implicated in the transdifferentiation of high-grade carcinomas. To improve our understanding of the role of EMT in these tumors, we studied a series of 89 carcinomas including 14 undifferentiated/dedifferentiated endometrial carcinomas (UECs/DECs), 49 CSs (21 endometrial, 29 tubo-ovarian and peritoneal), 17 endometrioid carcinomas (grade 1-3), and 9 high-grade serous carcinomas of the uterus, using a panel of antibodies targeting known epithelial markers (Pan-Keratin AE1/AE3 and E-cadherin), mesenchymal markers (N-cadherin), EMT transcription factors (TFs) (ZEB1, ZEB2, TWIST1), PAX8, estrogen receptors (ER), progesterone receptors (PR), and the p53 protein. At least one of the three EMT markers (more frequently ZEB1) was positive in the sarcomatous component of 98% (n = 48/49) of CSs and 98% (n = 13/14) of the undifferentiated component of UEC/DEC. In addition, 86% of sarcomatous areas of CSs and 79% of the undifferentiated component of UEC/DEC expressed all three EMT-TFs. The expression of these markers was associated with the loss of or reduction in epithelial markers (Pan-keratin, E-cadherin), PAX8, and hormone receptors. In contrast, none of the endometrioid and serous endometrial carcinomas expressed ZEB1, while 6% and 36% of endometrioid and 11% and 25% of serous carcinomas focally expressed ZEB2 and TWIST1, respectively. Although morphologically different, EMT appears to be implicated in the dedifferentiation in both CSs and UEC/DEC. Indeed, we speculate that the occurrence of EMT in a well differentiated endometrioid carcinoma may consecutively lead to a dedifferentiated and undifferentiated carcinoma, while in a type II carcinoma, it may result in a CS.

Combined activation of MAP kinase pathway and ß-catenin signaling cause deep penetrating nevi.

Deep penetrating nevus (DPN) is characterized by enlarged, pigmented melanocytes that extend through the dermis. DPN can be difficult to distinguish from melanoma but rarely displays aggressive biological behavior. Here, we identify a combination of mutations of the ß-catenin and mitogen-activated protein kinase pathways as characteristic of DPN. Mutations of the ß-catenin pathway change the phenotype of a common nevus with BRAF mutation into that of DPN, with increased pigmentation, cell volume and nuclear cyclin D1 levels. Our results suggest that constitutive ß-catenin pathway activation promotes tumorigenesis by overriding dependencies on the microenvironment that constrain proliferation of common nevi. In melanoma that arose from DPN we find additional oncogenic alterations. We identify DPN as an intermediate stage in the step-wise progression from nevus to melanoma. In summary, we delineate specific genetic alterations and their sequential order, information that can assist in the diagnostic classification and grading of these distinctive neoplasms.Deep penetrating nevi (DPN) are unusual melanocytic neoplasms with unknown genetic drivers. Here the authors show that majority of DPN harbor activating mutations in the ß-catenin and the MAP-kinase pathways; this characteristic can help in the classification and grading of these distinctive neoplasms.

The co-occurrence of an ovarian Sertoli-Leydig cell tumor with a thyroid carcinoma is highly suggestive of a DICER1 syndrome.

The DICER1 gene encodes an endoribonuclease involved in the production of mature microRNAs which regulates gene expression through several mechanisms. Carriers of germline DICER1 mutations are predisposed to a rare cancer syndrome, the DICER1 syndrome. Pleuropulmonary blastoma is the most frequent lesion seen in this syndrome. Thyroid abnormalities are also a common finding, essentially concerning multinodular goiter. However, differentiated thyroid carcinoma is infrequently seen in such pedigrees. In addition to germline DICER1 mutations, specific somatic mutations have been identified in the DICER1 RNase IIIb catalytic domain in several tumor types, including ovarian Sertoli-Leydig cell tumors. We report two cases of differentiated thyroid carcinoma associated with ovarian Sertoli-Leydig cell tumor and with a heterozygous DICER1 gene mutation, occurring in two unrelated young girls without pleuropulmonary blastoma. Both thyroid carcinomas showed an E1813 mutation in exon 25 while the ovarian tumors harboured a somatic mutation in E1705 in exon 24 and a D1709 mutation in exon 25. Our observations confirm that the occurrence of an ovarian Sertoli-Leydig cell tumor with a thyroid carcinoma is highly suggestive of a DICER1 syndrome. We contend that the possibility of a relationship between sporadic thyroid carcinoma in young patients and somatic DICER1 gene mutation needs further investigation.

Somatic DICER1 gene mutation in sporadic intraocular medulloepithelioma without pleuropulmonary blastoma syndrome.

Germline DICER1 gene mutation has been described in ocular medulloepithelioma associated with pleuropulmonary blastoma family tumor and dysplasia syndrome. We present a case of sporadic ocular medulloepithelioma in an 18-year-old woman with D1709N somatic mutation in DICER1 gene, which has not been previously described. This case highlights the potential use of DICER1 gene sequencing to resolve the diagnostic challenge in recurrent and metastatic malignant medulloepithelioma, when morphology and immunohistochemistry are inconclusive. Further studies in larger series of this type of tumor are needed to confirm the relevance of this molecular abnormality in the tumorigenesis of this embryonic-type ocular tumor.