Genetic alterations in goblet cell carcinoids of the vermiform appendix and comparison with gastrointestinal carcinoid tumors.

Goblet cell carcinoid is a relatively rare neuroendocrine tumor of the vermiform appendix with poorly understood molecular pathogenesis. We studied the clinicopathologic features and genetic alterations, including allelic loss of chromosomes 11q, 16q, and 18q; sequencing of the K-ras, beta-catenin, and DPC4 (SMAD4) genes; and p53 overexpression and loss of DPC4 by immunohistochemistry; in 16 goblet cell carcinoids. We compared the allelic loss in goblet cell carcinoids to those in 18 gastrointestinal carcinoid tumors. For goblet cell carcinoids, appendiceal perforation was the most common (70%, 7/10) clinical presentation. The mean tumor size was 2.0 +/- 1.5 cm (range, 0.4 to 4.5 cm). The tumor invaded to appendiceal serosa in 50% (8/16) of patients, and two patients had metastasis in lymph nodes or adjoining viscera. With mean follow-up of 24 +/- 14 months (median, 23 mo), 1 of 10 patients had died of disease, and 2 others had tumor recurrence. All four patients with metastases, recurrences, and/or death from disease had serosal involvement at presentation (P =.02). Loss of heterozygosity of chromosome 11q was present in 25% of goblet cell carcinoids, 14% of ileal carcinoid tumors, and 9% of nonileal carcinoid tumors; of chromosome 16q in 38%, 29%, and 0 (P =.02); and of chromosome 18q in 56%, 86%, and 9% (P =.002), respectively. No mutations of K-ras, beta-catenin, or DPC4 genes; p53 overexpression; or loss of staining for DPC4 was present in any tumors. These findings suggest that allelic loss of chromosomes 11q, 16q, and 18q in goblet cell carcinoids and ileal carcinoids may have an important role in the pathogenesis of these tumors.

K-ras mutation, p53 overexpression, and microsatellite instability in biliary tract cancers: a population-based study in China.

PURPOSE: The genetic alterations in biliary tract cancer and clinicopathological associations have not been studied in large population-based studies. EXPERIMENTAL DESIGN: We evaluated genetic alterations such as K-ras mutation, p53 overexpression, microsatellite instability (MSI), and alterations of the polyadenine tract present in the transforming growth factor beta receptor type II (TGFbetaRII) gene in 126 biliary tract cancers: 75 gallbladder cancers, 33 bile duct cancers, and 18 ampullary cancers. These genetic alterations were compared with patient demographics and clinicopathological characteristics of the tumors. RESULTS: Mutation of the K-ras gene was present in 18 of 126 (14.3%) biliary tract cancers. K-ras mutation was present in 11 of 18 (61.1%) ampullary cancers, 5 of 33 (15.2%) bile duct cancers, and 2 of 75 (2.7%) gallbladder cancers (P = 0.000001). The mean survival of patients who had bile duct carcinomas with K-ras mutation was 3.0 +/- 2.2 months compared with 15.5 +/- 12.5 months for those without mutation (P = 0.03) but was not different for other tumor sites. p53 overexpression was present in 34 of 123 (27.6%) cancers. MSI-high (allelic shifts in 40% or more loci or alteration of the TGFbetaRII gene) was present in 4 of 126 (3.2%) biliary tract cancers without hereditary nonpolyposis colorectal cancer. MSI-high was more common in mucinous adenocarcinomas (P = 0.006) and in patients with early age of onset of cancer (P = 0.04). CONCLUSIONS: The genetic alterations in biliary tract cancers are dependent on the tumor subsite, histology, and age of onset and are associated with prognosis.