Local recurrence after successful endoscopic submucosal dissection for rectal mucinous mucosal adenocarcinoma:A case report

BACKGROUND Mucinous adenocarcinoma of the colorectum is a rare histological subtype characterized by an abundant mucinous component.Mucinous tumors are frequently diagnosed at an advanced stage,which indicates an aggressive subtype.However,few case reports have been published,and little information is available concerning genetic alterations in mucinous adenocarcinoma.CASE SUMMARY A 76-year-old man underwent en bloc endoscopic submucosal dissection(ESD)for the management of a type 0-Is+IIa lesion.Histological examination revealed an intramucosal mucinous adenocarcinoma with signet-ring cell carcinoma and well-to-moderately differentiated tubular adenocarcinoma.Three years after the ESD,local recurrence was detected by an endoscopic examination,revealing a new 0-Is+IIa lesion with a phenotype similar to the previously resected lesion.Re-ESD was chosen for the management of the recurrent tumor,and the histological examination showed positive tumor infiltration at the vertical margin.Additional surgical resection was performed for the curative treatment.Genetic analysis showed pathogenic alterations in RNF43 and TP53 in the adenoma and an additional SMAD4 alteration in the carcinoma.CONCLUSION This mucinous mucosal adenocarcinoma case was suggested to have an aggressive phenotype and a careful and close follow-up are required.

Isoleucine, an Essential Amino Acid, Induces the Expression of Human <i>β</i>Defensin 2 through the Activation of the G-Protein Coupled Receptor-ERK Pathway in the Intestinal Epithelia

Anti-microbial peptides are essential for the intestinal innate immunity that protects the intestinal epithelia from attacks by foreign pathogens. Human β-defensin (HBD) is one of the pivotal anti-microbial peptides that are expressed in the colonic epithelia. This study investigated the effect and the signaling mechanism of inducible β-defensin HBD2 by an essential amino acid, isoleucine (Ile) in colonic epithelial cells. Here we examined the expression level of HBD2 on induction of Ile in epithelial cells, and checked this pathway. HBD2 mRNA was induced by co-incubation with IL-1α and Ile in Caco2 cells, but not by Ile alone. An inhibitor of either ERK or Gi, a subunit of G-proteins, reduced the induction of HBD2 mRNA by Ile. The treatment with Ile also increased the intracellular calcium ion concentration, thus suggesting that the GPCR and ERK signaling pathway mediate the effects of Ile. These results indicate that an essential amino acid, Ile, enhances the expression of an inducible β-defensin, namely HBD2, by IL-1α through the activation of GPCRs and ERK signaling pathway. The administration of Ile may therefore represent a possible option to safely treat intestinal inflammation.

Large-duct pattern invasive adenocarcinoma of the pancreas–a variant mimicking pancreatic cystic neoplasms: A minireview

Pancreatic cancer currently has no subtypes that inform clinical decisions;hence,there exists an opportunity to rearrange the morphological and molecular taxonomy that guides a better understanding of tumor characteristics.Nonetheless,accumulating studies to date have revealed the large-duct type variant,a unique subtype of pancreatic ductal adenocarcinoma(PDA)with cystic features.This subtype often radiographically mimics intraductal papillary mucinous neoplasms(IPMNs)and involves multiple small cysts occasionally associated with solid masses.The“bunch-of-grapes”sign,an imaging characteristic of IPMNs,is absent in large-duct PDA.Large-duct PDA defines the mucin profile,and genetic alterations are useful in distinguishing large-duct PDA from IPMNs.Histologically,neoplastic ducts measure over 0.5 mm,forming large ductal elements.Similar to classic PDAs,this subtype is frequently accompanied by perineural invasion and abundant desmoplastic reactions,and KRAS mutations in codon 12 are nearly ubiquitous.Despite such morphological similarities with IPMNs,the prognosis of large-duct PDA is equivalent to that of classic PDA.Differential diagnosis is therefore essential.