Mutação no gene beta-catenina

Estou bastante sem tempo por conta da faculdade, então vou só colocar aqui um estudo feito em 2008 por um dos centros especializados em desmóides dos Estados Unidos. Quando a poeira baixar eu traduzo pra vocês e conto as novidades :)

Am J Pathol. 2008 Nov;173(5):1518-27. Epub 2008 Oct 2.
Specific mutations in the beta-catenin gene (CTNNB1) correlate with local recurrence in sporadic desmoid tumors.

Lazar AJ, Tuvin D, Hajibashi S, Habeeb S, Bolshakov S, Mayordomo-Aranda E, Warneke CL, Lopez-Terrada D, Pollock RE, Lev D.

Sarcoma Research Center, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4001, USA.

Desmoid fibromatosis is a rare, nonmetastatic neoplasm marked by local invasiveness and relentless recurrence. Molecular determinants of desmoid recurrence remain obscure. beta-Catenin deregulation has been commonly identified in sporadic desmoids although the incidence of CTNNB1 (the gene encoding beta-catenin) mutations is uncertain. Consequently, we evaluated the prevalence of CTNNB1 mutations in a large cohort of sporadic desmoids and examined whether mutation type was relevant to desmoid outcome. Desmoid specimens (195 tumors from 160 patients, 1985 to 2005) and control dermal scars were assembled into a clinical data-linked tissue microarray. CTNNB1 genotyping was performed on a 138-sporadic desmoid subset. Immunohistochemical scoring was performed per standard criteria and data were analyzed using Kaplan-Meier and other indicated methods. CTNNB1 mutations were observed in 117 of 138 (85%) of desmoids. Three discrete mutations in two codons of CTNNB1 exon 3 were identified: 41A (59%), 45F (33%), and 45P (8%, excluded from further analysis because of rarity). Five-year recurrence-free survival was significantly poorer in 45F-mutated desmoids (23%, P < 0.0001) versus either 41A (57%) or nonmutated tumors (65%). Nuclear beta-catenin expression was observed in 98% of specimens and intensity was inversely correlated with incidence of desmoid recurrence (P < 0.01). In conclusion, CTNNB1 mutations are highly common in desmoid tumors. Furthermore, patients harboring CTNNB1 (45F) mutations are at particular risk for recurrence and therefore may especially benefit from adjuvant therapeutic approaches.

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