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Genome-wide association studies (GWAS) have been successful in identifying common genetic variation involved in susceptibility to etiologically complex disease. We conducted a GWAS to identify common genetic variation involved in susceptibility to upper aero-digestive tract (UADT) cancers. Genome-wide genotyping was carried out using the Illumina HumanHap300 beadchips in 2,091 UADT cancer cases and 3,513 controls from two large European multi-centre UADT cancer studies, as well as 4,821 generic controls. The 19 top-ranked variants were investigated further in an additional 6,514 UADT cancer cases and 7,892 controls of European descent from an additional 13 UADT cancer studies participating in the INHANCE consortium. Five common variants presented evidence for significant association in the combined analysis (p≤5×10−7). Two novel variants were identified, a 4q21 variant (rs1494961, p = 1×10−8) located near DNA repair related genes HEL308 and FAM175A (or Abraxas) and a 12q24 variant (rs4767364, p = 2×10−8) located in an extended linkage disequilibrium region that contains multiple genes including the aldehyde dehydrogenase 2 (ALDH2) gene. Three remaining variants are located in the ADH gene cluster and were identified previously in a candidate gene study involving some of these samples. The association between these three variants and UADT cancers was independently replicated in 5,092 UADT cancer cases and 6,794 controls non-overlapping samples presented here (rs1573496-ADH7, p = 5×10−8; rs1229984-ADH1B, p = 7×10−9; and rs698-ADH1C, p = 0.02). These results implicate two variants at 4q21 and 12q24 and further highlight three ADH variants in UADT cancer susceptibility.

Micrometastases have been detected by immunocytochemical means in the lymph nodes of patients with otherwise node-negative cancer of the colon and rectum. This study examines the incidence and prognostic significance of nodal micrometastases in Dukes' B carcinoma. Five hundred and fifty-nine lymph nodes from 77 cases of Dukes' B carcinoma were examined for lymph node micrometastases by immunocytochemical staining for cytokeratin AE1:AE3. Micrometastases were detected in 19 cases (25 per cent). Cell clusters were present in ten cases, the remaining nine cases displaying only single cells. The presence of micrometastases was unrelated to age (P = 0.06), sex (P = 0.32), tumour site (P = 0.37), tumour size (P = 0.67), or tumour differentiation (P = 0.66). Ten-year survival estimates by the Kaplan-Meier lifetable method was 47 per cent in patients with and without micrometastases (chi 2 = 0.35 and 1 df, P = ns). The presence of nodal micrometastases detectable only by immunocytochemistry in patients with Dukes' B colorectal cancer does not justify reassignment to a more advanced disease stage.

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