Burden and Profile of Somatic Mutation in Duodenal Adenomas from Patients with Familial Adenomatous- and MUTYH-associated Polyposis.

Purpose: Duodenal polyposis and cancer are important causes of morbidity and mortality in familial adenomatous polyposis (FAP) and MUTYH-associated polyposis (MAP). This study aimed to comprehensively characterize somatic genetic changes in FAP and MAP duodenal adenomas to better understand duodenal tumorigenesis in these disorders.Experimental Design: Sixty-nine adenomas were biopsied during endoscopy in 16 FAP and 10 MAP patients with duodenal polyposis. Ten FAP and 10 MAP adenomas and matched blood DNA samples were exome sequenced, 42 further adenomas underwent targeted sequencing, and 47 were studied by array comparative genomic hybridization. Findings in FAP and MAP duodenal adenomas were compared with each other and to the reported mutational landscape in FAP and MAP colorectal adenomas.Results: MAP duodenal adenomas had significantly more protein-changing somatic mutations (P = 0.018), truncating mutations (P = 0.006), and copy number variants (P = 0.005) than FAP duodenal adenomas, even though MAP patients had lower Spigelman stage duodenal polyposis. Fifteen genes were significantly recurrently mutated. Targeted sequencing of APC, KRAS, PTCHD2, and PLCL1 identified further mutations in each of these genes in additional duodenal adenomas. In contrast to MAP and FAP colorectal adenomas, neither exome nor targeted sequencing identified WTX mutations (P = 0.0017).Conclusions: The mutational landscapes in FAP and MAP duodenal adenomas overlapped with, but had significant differences to those reported in colorectal adenomas. The significantly higher burden of somatic mutations in MAP than FAP duodenal adenomas despite lower Spigelman stage disease could increase cancer risk in the context of apparently less severe benign disease. Clin Cancer Res; 23(21); 6721-32. ©2017 AACR.

The role of flow cytometry in celiac disease screening using human leukocyte antigen in adult patients with type 1 diabetes mellitus.

BACKGROUND: Patients with type 1 diabetes mellitus (DM1) have an increased risk of celiac disease (CD). Since CD can be seronegative, more sensible tests for detection are needed. In seronegative patients, CD diagnosis may be difficult because of a lack of specificity. Flow cytometry analysis of lymphocyte populations can be useful in this situation. We aimed to study the prevalence of CD in adult DM1 using human leukocyte antigen (HLA) compatibility-based screening. A secondary goal was to study the role of flow cytometry as a complementary tool in these patients. METHODS: We selected 200 patients with DM1, of whom 190 (95%) had HLA DQ2, DQ8 or both. Of these, 136 agreed to participate and provided epidemiological data. All patients underwent blood tests and gastroscopy. RESULTS: Sixteen patients had a histology consistent with CD. After ruling out other diagnoses, 6 patients were diagnosed with CD, 2 of whom had negative antibodies. All were DQ2.5 homozygous, with a CD prevalence of 9.8% in this group. In the flow cytometry analysis of duodenal biopsy samples, when we compared all non-CD with CD patients, we found that the γ/δ intraepithelial lymphocyte (IEL) percentage was significantly higher and the CD3 negative IEL percentage significantly lower in the CD group. We found similar results when we compared only those with histological lesions. CONCLUSIONS: Screening of CD in patients with DM1 by HLA detects only 1% of seronegative patients with CD. DQ2.5 homozygous patients are at most risk of developing CD. The study of lymphocyte populations in the duodenal biopsy by flow cytometry discriminates patients with CD from those without CD with high sensitivity and specificity.