DICER1-mutated rhabdomyosarcoma of the ovary with teratoid features.

DICER1-mutated rhabdomyosarcoma is a rare, emerging entity with a predilection for the gynecologic and genitourinary tracts. We report here a case of DICER1-mutated rhabdomyosarcoma of the ovary in a 14 years old girl which displayed interspersed mature teratoid glands, neuroectodermal rosettes and immature blastematous-like tubes. Morphologically the sarcomatous component predominated, corresponding to a high grade spindle cell rhabdomyosarcoma with botryoid features. Islets of cartilage were present. The sarcomatous proliferation encased the teratoid glands, forming cambium layer-like arrangements. The sarcoma cells were Myogenin and MYOD1 positive, the neuroectodermal rosettes expressed SALL4 along with cytokeratins and EMA and were negative for Inhibin; immature blastematous-like tubes were negative for SALL4 and Inhibin. Whole RNA- and targeted DNA-sequencing revealed two DICER1 mutations in exon 26: c.5113G>A: p.(Glu1705Lys) and exon 12: c.1642C>T: p.(Gln548X). The sarcomatous component harbored a complex genetic profile while the teratoid component was diploid, none of the above displayed abnormality of 12p. DICER1-mutated sarcomas display pathological features similar to embryonal rhabdomyosarcomas, botryoid type. They also display heterogeneous features combining cartilage foci, teratoid mature glands, immature blastematous-like tubes and/or neuroectodermal components. Molecular testing remains necessary to confirm the diagnosis. Further studies need to clarify the nosology of DICER1-mutated sarcomas and devise specific therapeutic strategies.

Tissue cholesterol metabolism and prostate cancer aggressiveness: Ethno-geographic variations.

BACKGROUND: Prostate cancer (PCa) is more frequent and more aggressive in populations of African descent than in Caucasians. Since the fatty acid composition of peri-prostatic adipose tissue (PPAT) has been shown to differ according to the ethno-geographic origin and is involved in PCa aggressiveness, we aimed to analyze the cholesterol content of PPAT from Caucasian and African-Caribbean patients, in correlation with markers of disease aggressiveness and cholesterol metabolism in cancer tissues. METHODS: The quantification of cholesterol in PPAT was analyzed in 52 Caucasian and 52 African-Caribbean PCa patients, with in each group 26 indolent tumors (ISUP Group1 and pT2) and 26 potentially aggressive tumors (ISUP Group 3-5 and/or pT3). The expression of proteins involved in cholesterol metabolism was analyzed by immunohistochemistry on cancer tissue samples included in tissue microarrays. RESULTS: The amount of cholesterol esters was lower in PPAT from African-Caribbean patients compared with Caucasians, without any correlation with markers of disease aggressiveness. In cancer tissues from African-Caribbean patients, the expression of ABCA1 (involved in cholesterol efflux) was decreased, and that of SREBP-2 (involved in cholesterol uptake) was increased. In both groups of patients, SREBP-2 expression was strongly associated with that of Zeb1, a key player in the epithelial-to-mesenchymal transition (EMT) process. CONCLUSION: These results suggest that cholesterol metabolism differs according to the ethno-geographic origin, in both PPAT and cancer tissues. In African-Caribbeans, the orientation towards accumulation of cholesterol in cancer cells is associated with a more frequent state of EMT, which may promote PCa aggressiveness in this population.