RESUMO
The group of incompletely differentiated (unclassified) sex cord/gonadal stromal tumors includes rare cases with predominant spindle cell morphology. We report a rare case of a "pure" spindle cell tumor of the testis with morphological and immunohistochemical features consistent with the diagnosis of "incompletely differentiated sex cord/gonadal stromal tumor". Given the spindle cell morphology, the differential diagnosis with other benign and malignant spindle cell lesions is discussed. The concurrent presence of some morphological and immunohistochemical features of both Leydig and granulosa cell lines in the tumor suggests its origin from a stromal stem cell, possibly capable of dual differentiation, but with an arrest of maturation at an early phase of differentiation.
Assuntos
Diferenciação Celular , Tumores do Estroma Gonadal e dos Cordões Sexuais/diagnóstico , Neoplasias Testiculares/diagnóstico , Adulto , Diagnóstico Diferencial , Células-Tronco de Carcinoma Embrionário , Feminino , Células da Granulosa/patologia , Humanos , Imuno-Histoquímica , Células Intersticiais do Testículo/patologia , Masculino , Células-Tronco Neoplásicas/patologia , Tumores do Estroma Gonadal e dos Cordões Sexuais/genética , Tumores do Estroma Gonadal e dos Cordões Sexuais/patologia , Células Estromais/patologia , Neoplasias Testiculares/genética , Neoplasias Testiculares/patologiaRESUMO
Inactivation of p53 and p73 is known to promote thyroid cancer progression. We now describe p63 expression and function in human thyroid cancer. TAp63alpha is expressed in most thyroid cancer specimens and cell lines, but not in normal thyrocytes. However, in thyroid cancer cells TAp63alpha fails to induce the target genes (p21Cip1, Bax, MDM2) and, as a consequence, cell cycle arrest and apoptosis occur. Moreover, TAp63alpha antagonizes the effect of p53 on target genes, cell viability and foci formation, and p63 gene silencing by small interfering (si) RNA results in improved p53 activity. This unusual effect of TAp63alpha depends on the protein C-terminus, since TAp63beta and TAp63gamma isoforms, which have a different arrangement of their C-terminus, are still able to induce the target genes and to exert tumour-restraining effects in thyroid cancer cells. Our data outline the existence of a complex network among p53 family members, where TAp63alpha may promote thyroid tumour progression by inactivating the tumour suppressor activity of p53.
