Distribution of cholecystokinin-B receptor genotype between patients with pancreatic cancer and controls and its impact on survival

Mechanisms of obesity- and diabetes mellitus-related pancreatic carcinogenesis: a comprehensive and systematic review

Research on obesity- and diabetes mellitus (DM)-related carcinogenesis has expanded exponentially since these two diseases were recognized as important risk factors for cancers. The growing interest in this area is prominently actuated by the increasing obesity and DM prevalence, which is partially responsible for the slight but constant increase in pancreatic cancer (PC) occurrence. PC is a highly lethal malignancy characterized by its insidious symptoms, delayed diagnosis, and devastating prognosis. The intricate process of obesity and DM promoting pancreatic carcinogenesis involves their local impact on the pancreas and concurrent whole-body systemic changes that are suitable for cancer initiation. The main mechanisms involved in this process include the excessive accumulation of various nutrients and metabolites promoting carcinogenesis directly while also aggravating mutagenic and carcinogenic metabolic disorders by affecting multiple pathways. Detrimental alterations in gastrointestinal and sex hormone levels and microbiome dysfunction further compromise immunometabolic regulation and contribute to the establishment of an immunosuppressive tumor microenvironment (TME) for carcinogenesis, which can be exacerbated by several crucial pathophysiological processes and TME components, such as autophagy, endoplasmic reticulum stress, oxidative stress, epithelial-mesenchymal transition, and exosome secretion. This review provides a comprehensive and critical analysis of the immunometabolic mechanisms of obesity- and DM-related pancreatic carcinogenesis and dissects how metabolic disorders impair anticancer immunity and influence pathophysiological processes to favor cancer initiation.

Insights into gastric neuroendocrine tumors burden

Type 1 gastric neuroendocrine tumors (gNETs) are usually small lesions, restricted to mucosal and sub-mucosal layers of corpus and fundus, with low aggressive behavior, for the majority of cases. Nevertheless, some cases present aggressive behavior. The increasing incidence of gNETs brings together a new relevant problem: how to identify potentially aggressive type 1 gNETs. The challenging problem seems to be finding out signs or features able to predict potentially aggressive cases, allowing a tailored approach, since the involved societies dedicated to provide guidelines for management of these neoplasms apparently failed in producing staging systems able to accurately predict prognosis of these tumors. Additionally, it is also important to try to find out explanations for increasing incidence, as well as to identify potential targets aiming to reach better control of this neoplasia. Here, we discuss potential pathways implicated in aggressive behavior, as well as new strategies to improve clinical management of these tumors.

A Common CCK-B Receptor Intronic Variant in Pancreatic Adenocarcinoma in a Hungarian Cohort

OBJECTIVES

Variant c.811+32C>A in intron 4 of the cholecystokinin-B receptor gene (CCKBR) was reported to correlate with higher pancreatic cancer risk and poorer survival. The variant was suggested to induce retention of intron 4, resulting in a new splice form with enhanced receptor activity. Our objective was to validate the c.811+32C>A variant as an emerging biomarker for pancreatic cancer risk and prognosis.

METHODS

We genotyped variant c.811+32C>A in 122 pancreatic adenocarcinoma case patients and 106 control subjects by sequencing and examined its association with cancer risk and patient survival. We tested the functional effect of variant c.811+32C>A on pre-messenger RNA splicing in human embryonic kidney 293T and Capan-1 cells transfected with CCKBR minigenes.

RESULTS

The allele frequency of the variant was similar between patients and control subjects (18.4% and 17.9%, respectively). Survival analysis showed no significant difference between median survival of patients with the C/C genotype (266 days) and patients with the A/C or A/A genotypes (257 days). CCKBR minigenes with or without variant c.811+32C>A exhibited no difference in expression of the intron-retaining splice variant.

CONCLUSION

These data indicate that variant c.811+32C>A in CCKBR does not have a significant impact on pancreatic cancer risk or survival in a Hungarian cohort.

The Role of Gastrin and CCK Receptors in Pancreatic Cancer and other Malignancies

The gastrointestinal (GI) peptide gastrin is an important regulator of the release of gastric acid from the stomach parietal cells and it also plays an important role in growth of the gastrointestinal tract. It has become apparent that gastrin and its related peptide cholecystokinin (CCK) are also significantly involved with growth of GI cancers as well as other malignancies through activation of the cholecystokinin-B (CCK-B) receptor. Of interest, gastrin is expressed in the embryologic pancreas but not in the adult pancreas; however, gastrin becomes re-expressed in pancreatic cancer where it stimulates growth of this malignancy by an autocrine mechanism. Strategies to down-regulate gastrin or interfere with its interface with the CCK receptor with selective antibodies or receptor antagonists hold promise for the treatment of pancreatic cancer and other gastrin--responsive tumors.

Germline Mutation of the CCK Receptor: A Novel Biomarker for Pancreas Cancer

Objectives:

Today, genetic biomarkers have been demonstrated to play an important role in identifying at-risk subjects for familial or inherited cancers. We have identified a single-nucleotide polymorphism (SNP) that results in missplicing of the cholecystokinin (CCK) receptor gene and expressing a larger mutated receptor in pancreatic cancer. The purpose of this study was to evaluate the significance and specificity of this SNP as a potential biomarker in patients with pancreatic cancer compared with other gastrointestinal (GI) cancers that also have CCK receptors.

Methods:

DNA was isolated and genotyped for the CCK receptor SNP from frozen tumor tissue from banked specimens of patients with pancreas, gastric, or colon cancer and from human cancer cell lines. Genotype and allelic frequencies were compared between the cancer cohort and two normal control databases using Fisher's exact test and odds ratio (OR). The Kaplan–Meier method was used to estimate the survival for patients with the CCK-B receptor SNP compared with those with the wild-type genotype. Immunohistochemical staining of cancer cells was done to detect the mutated receptor.

Results:

Colon and gastric cancer patients had similar genotype frequencies for the CCK receptor SNP as that reported in the normal population. In contrast, the prevalence of the SNP in subjects with pancreatic cancer was twice that of controls and other GI cancers. Survival was adversely affected by the presence of the SNP only in those with pancreatic cancer. Immunoreactivity for the mutated receptor was positive in pancreatic cancer tissues with the SNP but absent in other GI cancers.

Conclusions:

A SNP of the CCK receptor is significantly increased in patients with pancreatic cancer but not in those with other GI malignancies. Therefore, this SNP may be a potential biomarker for pancreatic cancer.