Adenosquamous gallbladder carcinoma: multigene hotspot mutational profiling reveals a monoclonal origin of the two components

Francesca Galuppinia, Roberta Salmasoa, Elisa Valentinia, Cristiano Lanzaa, Isacco Marettob, Donato Nittib, Massimo Ruggea, Matteo Fassana

a Department of Medicine (DIMED), Surgical Pathology Unit, University of Padua, Padua, Italy

b Department of Surgical, Oncological and Gastroenterological Sciences (DiSCOG), First Surgical Clinic Section, University of Padua, Padua, Italy

 

Abstract:

Adenosquamous carcinoma (ASC) of the gallbladder is a rare malignant tumor that is characterized by a coexisting of glandular and squamous components. In a case of ASC, we performed hotspot multigene mutational profiling of 164 hotspot regions of eleven cancer-associated genes (AKT1, APC, BRAF, CTNNB1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, PTEN and TP53) in the two microdissected components. Both tumor phenotypes resulted characterized by a p.E542 K point mutation in the PIK3CA gene, whereas adenocarcinoma component revealed also a TP53 Q331* homozygous stop mutation. Of note, coexisting high-grade dysplastic epithelium was characterized by a mixed cell population, with an upper part featuring a glandular differentiation and a basal layer of p63 positive (squamous committed) cells. Overall these data provide evidence of an early squamous differentiation of the lesion with a common genetic landscape of the two components.

 

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