SALL4 in gastrointestinal tract cancers: upstream and downstream regulatory mechanisms

Effective therapeutic targets and early diagnosis are major challenges in the treatment of gastrointestinal tract (GIT) cancers. SALL4 is a well-known transcription factor that is involved in organogenesis during embryonic development. Previous studies have revealed that SALL4 regulates cell proliferation, survival, and migration and maintains stem cell function in mature cells. Additionally, SALL4 overexpression is associated with tumorigenesis. Despite its characterization as a biomarker in various cancers, the role of SALL4 in GIT cancers and the underlying mechanisms are unclear. We describe the functions of SALL4 in GIT cancers and discuss its upstream/downstream genes and pathways associated with each cancer. We also consider the possibility of targeting these genes or pathways as potential therapeutic options for GIT cancers.

Current status of gastrointestinal tract cancer brain metastasis and the use of blood-based cancer biomarker biopsy

Brain metastasis (BM) frequently occurs in patients with cutaneous melanoma, lung, and breast cancer; although, BM rarely arises from cancers of the gastrointestinal tract (GIT). The reported incidence of GIT cancer BM is less than 4%. In the last few years, effective systemic therapy has prolonged the survival of GIT patients and consequently, the incidence of developing BM is rising. Therefore, the epidemiology and biology of BM arising from GIT cancer requires a more comprehensive understanding. In spite of the development of new therapeutic agents for patients with metastatic GIT cancers, survival for patients with BM still remains poor, with a median survival after diagnosis of less than 4 months. Limited evidence suggests that early detection of isolated intra-cranial lesions will enable surgical resection plus systemic and/or radiation therapy, which may lead to an increase in overall survival. Novel diagnostic methods such as blood-based biomarker biopsies may play a crucial role in the early detection of BM. Circulating tumor cells and circulating cell-free nucleic acids are known to serve as blood biomarkers for early detection and treatment response monitoring of multiple cancers. Blood biopsy may improve early diagnosis and treatment monitoring of GIT cancers BM, thus prolonging patients' survivals.

Ultrasonography in infectious and neoplastic diseases of the bowel and peritoneum

Ultrasonography is not the most cited imaging technique for the evaluation of infectious and neoplastic diseases of the gastrointestinal tract and the peritoneum, but it is often the initial technique used in the initial workup for nonspecific clinical syndromes. Despite its limitations, ultrasonography's strengths enable it to provide meaningful diagnostic information. To discuss the most important ultrasonographic, clinical, and epidemiological findings for infectious disease, we follow a topographical approach: stomach (Anisakis), proximal small bowel (Giardia lamblia, Strongyloides stercoralis, Mycobacterium avium-intracellulare complex, and Cryptosporidium), distal small bowel (Yersinia, Salmonella, and Campylobacter), terminal ileum and cecum (tuberculosis), right colon (Entamoeba histolytica), left colon (Shigella), sigmoid colon and rectum, pancolitis (Clostridium difficile, Cytomegalovirus, and Escherichia coli), and peritoneum. To discuss the ultrasonographic and clinical findings of the most common neoplastic diseases, we follow a nosological approach: polyploid lesions as precursors of tumors, carcinomas, neuroendocrine tumors, hematological tumors, mesenchymal tumors, and metastases. We briefly discuss tumors of the peritoneum and the use of ultrasonography to guide percutaneous biopsy procedures.

Inflammatory bowel disease and risk of gastric, small bowel and colorectal cancer: a meta-analysis of 26 observational studies

PURPOSE

The purpose of this meta-analysis was to assess the associations between inflammatory bowel disease (IBD) and risk of the gastric, small bowel and colorectal cancer.

METHODS

We searched the PubMed and Web of Science for observational studies published before June 2020, and the quality of each included study was evaluated according to the Newcastle-Ottawa-Scale.

RESULTS

Twenty-six studies comprising 531 449 IBD patients and more than 65 million reference individuals were included. Although IBD was significantly associated with 67% increased risk of the total gastric, small bowel and colorectal cancer. After stratifying by cancer location, IBD mainly increased the risk of intestinal cancer instead of gastric cancer. Furthermore, Crohn's disease (CD) significantly increased the risk of both small bowel cancer and colorectal cancer, while ulcerative colitis (UC) only increased the risk of colorectal cancer. In subgroup analysis, associations between IBD and risk of total gastric, small bowel and colorectal cancer were similar between male and female, except for that male IBD patients but not female had a significantly higher risk of small bowel cancer. Additionally, IBD patients in different geographical areas had different associations with risk of various gastrointestinal tract cancers.

CONCLUSIONS

IBD is mainly associated with increased risk of cancers in the lower gastrointestinal tract, including small bowel cancer and colorectal cancer. Because studies about the association between IBD and risk of gastric cancer and the populations in Asia are limited, more observational studies are required in the future.

SWI/SNF-deficient cancers of the Gastroenteropancreatic tract: an in-depth review of the literature and pathology

The SWItch Sucrose non-fermentable (SWI/SNF) complex is a large, multi-subunit ATP-dependent nucleosome remodeling complex that acts as a tumor suppressor by modulating transcription. Mutations of SWI/SNF subunits have been described in relation to developmental disorders, hereditary SWI/SNF deficiency syndromes, as well as malignancies. In this review we summarize the current literature in regards to SWI/SNF-deficient tumors of the luminal gastrointestinal tract (GIT) and pancreas. As a group they range from moderately to undifferentiated tumors composed of monotonous anaplastic cells, prominent macronucleoli and a variable rhabdoid cell component. Deficiency of a SWI/SNF subunit is typified by complete loss of nuclear staining by immunohistochemistry for respective subunit.

Discordant DNA mismatch repair protein status between synchronous or metachronous gastrointestinal carcinomas: frequency, patterns, and molecular etiologies

The widespread use of tumor DNA mismatch repair (MMR) protein immunohistochemistry in gastrointestinal tract (GIT) carcinomas has unveiled cases where the MMR protein status differs between synchronous/metachronous tumors from the same patients. This study aims at examining the frequency, patterns and molecular etiologies of such inter-tumoral MMR discordances. We analyzed a cohort of 2159 colorectal cancer (CRC) patients collected over a 5-year period and found that 1.3% of the patients (27/2159) had ≥ 2 primary CRCs, and 25.9% of the patients with ≥ 2 primary CRCs (7/27) exhibited inter-tumoral MMR discordance. We then combined the seven MMR-discordant CRC patients with three additional MMR-discordant GIT carcinoma patients and evaluated their discordant patterns and associated molecular abnormalities. The 10 patients consisted of 3 patients with Lynch syndrome (LS), 1 with polymerase proofreading-associated polyposis (PAPP), 1 with familial adenomatous polyposis (FAP), and 5 deemed to have no cancer disposing hereditary syndromes. Their MMR discordances were associated with the following etiologies: (1) PMS2-LS manifesting PMS2-deficient cancer at an old age when a co-incidental sporadic MMR-proficient cancer also occurred; (2) microsatellite instability-driven secondary somatic MSH6-inactivation occurring in only one-and not all-PMS2-LS associated MMR-deficient carcinomas; (3) "compound LS" with germline mutations in two MMR genes manifesting different tumors with deficiencies in different MMR proteins; (4) PAPP or FAP syndrome-associated MMR-proficient cancer co-occurring metachronously with a somatic MMR-deficient cancer; and (5) non-syndromic patients with sporadic MMR-proficient cancers co-occurring synchronously/metachronously with sporadic MMR-deficient cancers. Our study thus suggests that inter-tumoral MMR discordance is not uncommon among patients with multiple primary GIT carcinomas (25.9% in patients with ≥ 2 CRCs), and may be associated with widely varied molecular etiologies. Awareness of these patterns is essential in ensuring the most effective strategies in both LS detection and treatment decision-making. When selecting patients for immunotherapy, MMR testing should be performed on the tumor or tumors that are being treated.

Off-label use of common predictive biomarkers in gastrointestinal malignancies: a critical appraisal

The use of immunohistochemistry (IHC) as a companion diagnostic is an increasingly important part of the case workup by pathologists and is often central to clinical decision making. New predictive molecular markers are constantly sought for to improve treatment stratification parallel to drug development. Unfortunately, official biomarker guidelines lag behind, and pathologists are often left hesitating when medical oncologists request off-labelled biomarker testing. We performed a literature review of five commonly requested off-label IHC predictive biomarkers in gastrointestinal tract (GIT) malignancies: HER2, mismatch repair (MMR), PD-L1, BRAF V600E and ROS1. We found that HER2 amplification is rare and poorly associated to IHC overexpression in extracolonic and extragastric GIT cancers; however in KRAS wild type colorectal cancers, which fail conventional treatment, HER2 IHC may be useful and should be considered. For MMR testing, more evidence is needed to recommend reflex testing in GIT cancers for treatment purposes. MMR testing should not be discouraged in patients considered for second line checkpoint inhibitor therapy. With the exception of gastric tumors, PD-L1 IHC is a weak predictor of checkpoint inhibitor response in the GIT and should be replaced by MMR in this context. BRAF inhibitors showed activity in BRAF V600E mutated cholangiocarcinomas and pancreatic carcinomas in non-first line settings. ROS1 translocation is extremely rare and poorly correlated to ROS1 IHC expression in the GIT; currently there is no role for ROS1 IHC testing in GIT cancers. Overall, the predictive biomarker literature has grown exponentially, and official guidelines need to be updated more regularly to support pathologists’ testing decisions.

A Pipeline for ctDNA Detection Following Primary Tumor Profiling Using a Cancer-Related Gene Sequencing Panel

Circulating tumor DNA (ctDNA) is emerging as a promising biomarker for cancer diagnosis. However, the system to detect gene mutations with very low frequencies from plasma remains to be established in terms of technical aspects of sequencing technologies and cost for universal use. One strategy is to employ a cancer sequencing panel to detect mutations in a primary tumor in a time- and cost-effective manner, and subsequently assess these mutations with a digital PCR technology from plasma ctDNA. This strategy enables the accurate detection of low frequency mutations (i.e., less than 1% allele frequency) from ctDNA, since both comprehensive coverage of genes and quantitative mutation detection with very low frequencies are required for cancer diagnosis from plasma samples. Here, we present a pipeline can be used to detect mutations from plasma ctDNA with very low allele frequencies using a next-generation sequencing technology for comprehensive coverage of primary tumors and droplet digital PCR for sensitive detection from plasma ctDNA.

Predicting liver metastasis of gastrointestinal tract cancer by diffusion-weighted imaging of apparent diffusion coefficient values

AIM: To determine if efficacy of chemotherapy on liver metastasis of gastrointestinal tract cancer can be predicted by apparent diffusion coefficient (ADC) values of diffusion-weighted imaging (DWI).

METHODS: In total, 86 patients with liver metastasis of gastrointestinal tract cancer (156 metastatic lesions) diagnosed in our hospital were included in this study. The maximum diameters of these tumors were compared with each other before treatment, 2 wk after treatment, and 12 wk after treatment. Selected patients were classified as the effective group and the ineffective group, depending on the maximum diameter of the tumor after 12 wk of treatment; and the ADC values at different treatment times between the two groups were compared. Spearman rank correlation was used to analyze the relationship between ADC value and tumor diameter. Receiver operating characteristic curve (ROC curve) was used to analyze the ADC values before treatment to predict the patient’s sensitivity and specificity degree of efficacy to the chemotherapy.

RESULTS: There was no difference in age between the two groups and in maximum tumor diameter before treatment and 2 wk after treatment. However, after 12 wk of treatment, maximum tumor diameter in the effective group was significantly lower than that in the ineffective group (P < 0.05). Before treatment, ADC values in the ineffective group were significantly higher than those in the effective group (P < 0.05). There was no difference in ADC values between the effective and ineffective groups after 2 and 12 wk of treatment. However, ADC values were significantly higher after 2 and 12 wk of treatment compared to before treatment in the effective group (P < 0.05). Spearman rank correlation analysis showed that ADC value before treatment and the reduced percentage of the maximum tumor diameter after 12 wk of treatment were negatively correlated, while the increase in the percentage of the ADC value 12 wk after treatment and the decrease in the percentage of the maximum tumor diameter were significantly positively correlated. The results of the ROC curve showed that ADC value with a chemotherapy ineffective threshold value of 1.14 × 10^-3 mm²/s before treatment had a sensitivity and specificity of 94.3% and 76.7%, respectively.

CONCLUSION: DWI ADC values can be used to predict the response of patients with liver metastasis of gastrointestinal tract cancer to chemotherapy with high sensitivity and relatively high specificity.

Bisphosphonate use and gastrointestinal tract cancer risk: Meta-analysis of observational studies

AIM: To perform a meta-analysis of observational studies to further elucidate the relationship between oral bisphosphonate use and gastrointestinal cancer risk.

METHODS: Systematic literature search was conducted in MEDLINE, EMBASE, and the Cochrane Library to identify studies through January 2011. Search terms were “bisphosphonates” or trade names of the drugs, and “observational studies” or “cohort studies” or “case-control studies”. Two evaluators reviewed and selected articles on the basis of predetermined selection criteria as followed: (1) observational studies (case-control or cohort studies) on bisphosphonate use; (2) with at least 2 years of follow-up; and (3) reported data on the incidence of cancer diagnosis. The DerSimonian and Laird random effects model were used to calculate the pooled relative risk (RR) with 95% confidence interval (CI). Two-by-two contingency table was used to calculate the outcomes not suitable for meta-analysis. Subgroup meta-analyses were conducted for the type of cancer (esophageal, gastric and colorectal cancers). Sensitivity analyses were performed to examine the effect sizes when only studies with long-term follow-up (mean 5 years; subgroup 3 years) were included.

RESULTS: Of 740 screened articles, 3 cohort studies and 3 case-control studies were included in the analyses. At first, 4 cohort studies and 3 case-control studies were selected for the analyses but one cohort study was excluded because the cancer outcomes were not categorized by type of gastrointestinal cancer. More than 124 686 subjects participated in the 3 cohort studies. The mean follow-up time in all of the cohort studies combined was approximately 3.88 years. The 3 case-control studies reported 3070 esophageal cancer cases and 15 417 controls, 2018 gastric cancer cases and 10 007 controls, and 11 574 colorectal cancer cases and 53 955 controls. The percentage of study participants who used bisphosphonate was 2.8% among the cases and 2.9% among the controls. The meta-analysis of all the studies found no significant association between bisphosphonate use and gastrointestinal cancer. Also no statistically significant association was found in a meta-analysis of long-term follow-up studies. There was no negative association between bisphosphonate use and the incidence of esophageal cancer in the overall analysis (RR 0.96, 95% CI: 0.65-1.42, I² = 52.8%, P = 0.076) and no statistically significant association with long-term follow-up (RR 1.74, 95% CI: 0.97-3.10, I² = 58.8%, P = 0.119). No negative association was found in the studies reporting the risk of gastric cancer (RR 0.89, 95% CI: 0.71-1.13, I² = 0.0%, P = 0.472). In case of colorectal cancer, there was no association between colorectal cancer and bisphosphonate use (RR 0.62, 95% CI: 0.30-1.29, I² = 88.0%, P = 0.004) and also in the analysis with long-term follow-up (RR 0.61, 95% CI: 0.28-1.35, I² = 84.6%, P = 0.011).

CONCLUSION: Oral bisphosphonate use had no significant effect on gastrointestinal cancer risk. However, this finding should be validated in randomized controlled trials with long-term follow-up.

Expected survival using models of life table compared with survival of gastrointestinal tract cancer patients in north of iran

BACKGROUND

Northern regions of Iran have been encountered to dominate malignancies of gastrointestinal (GI) tract. We came to examine the total excess mortality due to the GI cancer in Mazandaran province.

METHODS

Socio-demographic and clinical data of 484 patients with GI cancer collected during the years 1990-1991 were available from Babol Cancer Registry. Patients were followed up for 15 years by the year 2006. Using the West Coale-Demeny life table model, a number of five life tables for men and four for women, corresponding to each birth cohort, were constructed. Observed survival was obtained using the Kaplan-Meier method and compared with the Expected survival calculated using the direct adjusted method represented by STEIN et al.

RESULTS

The sample of subjects encompassed 66.3% men and 33.7% women with mean age 58.26 ± 10.90, and endoscopy was the general method for cancer detection. Esophagus accounted for 74.2%, and stomach and colorectal accounted for 22.7% and 3.1% of GI cancers, respectively. Survival rate in 15 years following diagnosis was nearly 6%. Comparing patient and expected survival curves showed a significantly reduced survival for patients of each GI cancer over the whole period and especially during the first two years after diagnosis.

CONCLUSION

Patients experienced reduced survival associated with the development of GI cancers. Considering individuals in a population come from different cohorts, adjustment by constructing distinct life tables for different birth cohorts is recommended. The West model is recommended as a first choice to represent mortality in countries whose registration systems are exposed to various errors.