Background: Relapse and metastasis in colorectal cancer (CRC) are often attributed to cancer stem-like cells (CSCs), as small sub-population of tumor cells with ability of drug resistance. Accordingly, development of appropriate models to investigate CSCs biology and establishment of effective therapeutic strategies is warranted. Hence, we aimed to assess the capability of two widely used and important colorectal cancer cell lines, HT-29 and Caco-2, in generating spheroids and their detailed morphological and molecular characteristics.Methods: CRC spheroids were developed using hanging drop and forced floating in serum-free and non-attachment conditions and their morphological features were evaluated by scanning electron microscopy (SEM). Then, the potential of CSCs enrichment in spheroids was compared to their adherent counterparts by analysis of serial sphere formation capacity, real-time PCR of key stemness genes (KLF4,OCT4,SOX2,NANOG,C-MYC) and the expression of potential CRC-CSCs surface markers (CD166, CD44, and CD133) by flow cytometry. Finally, the expression level of some EMT-related (Vimentin,SNAIL1,TWIST1,N-cadherin,E-cadherin,ZEB1) and multi-drug resistant (ABCB1,ABCC1,ABCG2) genes was evaluated.Results: Although with different morphological features, both cell lines were formed CSCs-enriched spheroids, indicated by ability to serial sphere formation, significant up-regulation of stemness genes,SOX2,C-MYC, NANOGandOCT4in HT-29 andSOX2,C-MYCandKLF4in Caco-2 spheroids (p-value < 0.05) and increased expression of CRC-CSC markers compared to parental cells (p-value < 0.05). Additionally, HT-29 spheroids exhibited a significant higher expression of bothABCB1andABCG2(p-value = 0.02). The significant up-regulation of promoting EMT genes,ZEB1,TWIST1,E-cadherinandSNAIL1in HT-29 spheroids (p-value = 0.03),SNAIL1andVimentinin Caco-2 spheroids (p-value < 0.05) andN-cadherindown-regulation in both spheroids were observed.Conclusion: Enrichment of CSC-related features in HT-29 and Caco-2 (for the first time without applying special scaffold/biochemical) spheroids, suggests spheroid culture as robust, reproducible, simple and cost-effective model to imitate the complexity of in vivo tumors including self-renewal, drug resistance and invasion for in vitro research of CRC-CSCs.

Metastasis is the most frequent type of recurrence in gastrointestinal (GI) cancers, and there is an emerging potential for new diagnostic and therapeutic approaches, especially in the cases of metastatic GI carcinomas. The expression profiles of circulating exosomal microRNAs are of particular interest as novel non-invasive diagnostic and prognostic biomarkers for improved detection of GI cancers in body fluids, especially in the serum of patients with recurrent cancers. The aim of this study is to systematically review primary studies and identify the miRNA profiles of serum exosomes of GI cancers. This systematic review will be reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidance. Relevant studies will be identified through a comprehensive search of the following main electronic databases: PubMed, Web of Science, Embase, Scopus, and Google Scholar, with no language restrictions (up to July 2017). Full copies of articles will be identified by a defined search strategy and will be considered for inclusion against pre-defined criteria. The quality assessment of the included studies will be performed by the Newcastle-Ottawa Scale (NOS). Data will be analyzed using Stata software V.12. Publication bias will be assessed by funnel plots, Beggs’ and Eggers’ tests. The levels of evidence for primary outcomes will be evaluated using the GRADE criteria. The analysis of circulating exosomal miRNA profiles provides attractive screening and non-invasive diagnostic tools for the majority of solid tumors including GI cancers. There is limited information regarding the relationship between serum exosomal miRNA profiles and the pathological condition of patients with different GI cancers. Since there is no specific biomarker for GI cancers, we aim to suggest a number of circulating exosomal miRNA candidates as potential multifaceted GI cancer biomarkers for clinical utility. PROSPERO CRD42017057129

Background: The significance of epidermal growth factor receptor (EGFR) gene variants, particularly the variant known as EGFRvIII, which arises from the deletion of exons 2–8, has been extensively studied in various human carcinomas. In contrast, studies into the role of EGFRvIII in gastric cancer remain limited. The current study aims to evaluate the expression levels of EGFRvIII in patients suffering from gastric adenocarcinoma. Material and methods: In this descriptive cross‐sectional study, 21 patients with gastric adenocarcinoma who referred to the university‐based referral hospital, Rasoul‐Akram, in Tehran, Iran, during 2018–2019, were included. The patients’ characteristics including demographic features, medical archives, type and location of tumor mass, and histopathological type were recorded. In order to evaluate the expression of EGFRvIII variant, RT‐PCR and sequencing techniques were used. Results: In patients with gastric adenocarcinoma, 14 cases (66.7%) were males and seven cases (33.3%) were females, and the average age of the patients was 66.62 ± 10.79 years, ranging from 45 to 89 years. In terms of the histopathological type, six cases (28.6%) were moderately differentiated (MD), four cases (19.0%) were poorly differentiated (PD), five cases (23.8%) were SIG adenocarcinoma, and six cases (28.6%) were well differentiated (WD). A total of 18 samples (85.7%) were obtained from the biopsy, while three cases (14.3%) were derived from total gastrectomy and necrosis was seen in eight cases (38.1%). Two out of 21 cases (9.5%) were EGFRvIII positive in both RT‐PCR and sequencing test. The first case was an 86‐year‐old woman with a signet‐ring cell (SIG) adenocarcinoma tumor subtype with tissue from the antrum and without necrosis. The second case was a 67‐year‐old man with a tumor subtype of SIG adenocarcinoma with necrotic tissue sample from the gastric cavity. The location of the mutation, two genes on ex1 and ex8, which were connected to each other, was detected in samples of both cases. Conclusion: Our findings showed detection of EGFRvIII in 9.5% of gastric adenocarcinoma cases. Although the sample size presents a limitation, the increase in expression of this variant appears to be independent of the patients’ gender and age. Notably, the association of this variant with the signet‐ring cell adenocarcinoma subtype is a significant finding that warrants further investigation.