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DNA methylation alterations are early events during tumourigenesis, affecting genes involved in the crosstalk between cells and surroundings in colorectal cancer (CRC). Among these genes, GRIA4, Glutamate Ionotropic Receptor AMPA Type Subunit 4, displays hypermethylation in the promoter region, and is an early diagnostic biomarker. It is well known that methylation can also affect alternative transcription. The purpose of this study is to evaluate the expression, at transcript and protein level, of GRIA4 main isoforms (the canonical one and a short variant) in 23 CRC and matched normal samples, of which we previously verified the methylation status. We further predicted miRNA/transcript target interactions as a possible post-transcriptional regulation using bioinformatics tools. As expected, downregulation of both variants has been observed in tumours. Interestingly, in contrast to what observed at transcriptional level, the GluR4 protein short isoform displayed higher expression than the canonical one either in normal or tumoural tissues. This may be explained by miRNA specifically targeting the canonical isoform. Our study is the first one that shows the expression of both isoforms in colon tissues. To note, the evident expression of the short isoform suggests a functional role in intestinal cell biology., (© 2021. The Author(s).)

Endoscopy remains the main technique in the diagnosis and treatment of Crohn's disease (CD); nevertheless, the recent development of innovative and non-invasive imaging techniques has led to a new tool in the exploration of small bowel in CD patients. This paper reviews the available data on ultrasound imaging used for the evaluation of CD, highlighting the role of small intestine contrast-enhanced ultrasonography with the use of oral and intravenous contrast agents.

Background: Accurate preoperative staging is the key to correct selection of rectal tumors for local excision. This study aims to assess the accuracy of endorectal ultrasound (ERUS) at our institution., Patients and Methods: Retrospective analysis was carried out of patients treated by transanal endoscopic microsurgery (TEM) from 1996 to 2008. TEM was considered the treatment of choice for uT0-1/N0 lesions located between 2 and 12 cm from the anal verge. It was also proposed in selected uT2-3 patients. Preoperative staging was compared with histopathologic findings., Results: Eighty-one patients (46 males, mean age 66 years) underwent TEM. Mean distance of the tumor from the anal verge was 6.6 cm (range 2-12 cm). ERUS staged 15 of 27 adenomas (55%) as uT1. Of 54 carcinomas, 5 were pT0 because TEM was performed to remove resection margins of a malign polyp already snared. Five of 19 pTis (26%) were overstaged uT1, while 7 of 17 pT1 (41%) were understaged. Overall, ERUS enabled distinction between early and advanced rectal lesion with 96% sensitivity and 85% specificity, giving accuracy of 94% (65/67). Thirteen patients had advanced lesions (eight pT2 and five pT3). Only in two of them (15%) was depth of invasion underestimated by ERUS (one uT0, one uT1) and thus was subsequent salvage surgery necessary., Conclusions: ERUS is useful to confirm the diagnosis of adenoma and predict depth of mural invasion in early rectal cancer. Differentiation between T0/is and T1 lesions remains challenging, however this does not usually influence surgical strategy.