The Desmoid Tumor Research Foundation

August 2018

Novel intra-genic large deletions of CTNNB1 gene identified in WT desmoid-type fibromatosis

Author Information

Colombo C(1), Urbini M(2), Astolfi A(2), Collini P(3), Indio V(2), Belfiore A(3),Paielli N(3), Perrone F(3), Tarantino G(2), Palassini E(4), Fiore M(1), PessionA(2), Stacchiotti S(4), Pantaleo MA(2)(5), Gronchi A(1).

(1)Dept of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano,Italy (2)"Giorgio Prodi" Cancer Research Center, University of Bologna, Bologna, Italy. (3)Dept of Pathology, Fondazione IRCCS Istituto Nazionale dei Tumori,Milano, Italy. (4)Dept of Cancer Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori,Milano, Italy. (5)Dept of Specialized, Experimental & Diagnostic Medicine,Sant'Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.

Publication

Genes Chromosomes Cancer

Summary

A wait and see approach for desmoid tumors (DT) has become part of the routine treatment strategy. However, predictive factors to select the risk of progressive disease are still lacking. A translational project was run in order to identify genomic signatures in patients enrolled within an Italian prospective observational study. Among 12 DT patients (ten CTNNB1-mutated and two WT) enrolled from our Institution only two patients (17%) showed a progressive disease. Tumor biopsies were collected for whole exome sequencing. Overall, DT exhibited low somatic sequence mutation rate and no additional recurrent mutation was found. In the two WT cases, two novel alterations were detected: a complex deletion of APC and a pathogenic mutation of LAMTOR2. In conclusion, a minority of DT is WT for either CTNNB1, APC or any other gene involved in the WNT pathway. In this subgroup novel and hard to be detected molecular alterations in APC and CTNNB1 were discovered, contributing to explain a portion of the allegedly WT DT cases.

View Abstract