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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