REG Iα is a biomarker for predicting response to chemotherapy with S-1 plus cisplatin in patients with unresectable stage IV gastric cancer

The Potential Role of REG Family Proteins in Inflammatory and Inflammation-Associated Diseases of the Gastrointestinal Tract

Regenerating gene (REG) family proteins serve as multifunctional secretory molecules with trophic, antiapoptotic, anti-inflammatory, antimicrobial and probably immuno-regulatory effects. Since their discovery, accumulating evidence has clarified the potential roles of the REG family in the occurrence, progression and development of a wide range of inflammatory and inflammation-associated diseases of the gastrointestinal (GI) tract. However, significant gaps still exist due to the undefined nature of certain receptors, regulatory signaling pathways and possible interactions among distinct Reg members. In this narrative review, we first describe the structural features, distribution pattern and purported regulatory mechanisms of REG family proteins. Furthermore, we summarize the established and proposed roles of REG proteins in the pathogenesis of various inflammation-associated pathologies of the GI tract and the body as a whole, focusing particularly on carcinogenesis in the ulcerative colitis—colitic cancer sequence and gastric cancer. Finally, the clinical relevance of REG products in the context of diagnosis, treatment and prognostication are also discussed in detail. The current evidence suggests a need to better understanding the versatile roles of Reg family proteins in the pathogenesis of inflammatory-associated diseases, and their broadened future usage as therapeutic targets and prognostic biomarkers is anticipated.

Role of the β-Catenin/REG Iα Axis in the Proliferation of Sessile Serrated Adenoma/Polyps Associated with Fusobacterium nucleatum

Although sessile serrated adenoma/polyps (SSA/Ps) may arise through a pathway different from the traditional adenoma–carcinoma sequence, details of SSA/P tumorigenesis still remain unclear. Fusobacterium nucleatum (Fn) is frequently detected in colorectal cancer (CRC) tissues and may play a pivotal role in colorectal carcinogenesis. Here, we investigated the relationship between Fn and the β-catenin/REG Iα axis in SSA/Ps and their involvement in the proliferation of these lesions. Fn was detected in SSA/Ps by fluorescence in situ hybridization using a Fn-targeted probe, and expression of β-catenin, REG Iα and Ki67 was examined using immunohistochemistry. Sixteen of 30 SSA/P lesions (53.3%) were positive for Fn. Eighteen SSA/P lesions (60%) showed β-catenin immunoreactivity in the tumor cell nuclei. A significant majority of Fn-positive lesions showed nuclear expression of β-catenin (87.5%) and higher REG Iα scores and Ki67 labeling indices relative to Fn-negative lesions. The SSA/P lesions expressing β-catenin in nuclei had significantly higher REG Iα scores and Ki67 labeling indices than those expressing β-catenin on cytomembranes. The REG Iα score was positively correlated with the Ki67 labeling index in SSA/P lesions. The treatment with Wnt agonist SKL2001 promoted nuclear β-catenin translocation and enhanced REG Ia expression in Caco2 cells. Fn may play a role in the proliferation of SSA/P lesions through promotion of β-catenin nuclear translocation and REG Iα expression.

Carboxypeptidase A1 and regenerating islet-derived 1α as new markers for pancreatic acinar cell carcinoma

Acinar cell carcinoma (ACC) is a rare tumor that differentiates toward pancreatic acinar cells and shows evidence of pancreatic enzyme production. Mixed acinar-neuroendocrine carcinoma (MANC) is defined as having more than 30% of both acinar and neuroendocrine cell types as per immunohistochemistry analysis. Trypsin is currently the most commonly used stain for acinar differentiation. In this study, we investigate the utility of two novel markers, carboxypeptidase A1 (CPA1) and regenerating islet-derived 1α (REG1a), in diagnosing ACC/MANC. Immunohistochemical staining for CPA1 and REG1a was performed on 14 cases of ACC and 5 cases of MANC as well as on 80 other pancreatic tumors including 20 cases each of ductal adenocarcinoma, well-differentiated neuroendocrine tumor, mucinous cystic neoplasm, and solid pseudopapillary tumor. All ACCs and MANCs were positive for CPA1 (all diffuse) and REG1a (12 diffuse, 4 patchy, and 3 focal). A diffuse or patchy staining pattern was significantly more common in ACC/MANC cases (100% diffuse/patchy for CPA1 and 84% for REG1a) than in other pancreatic tumors (5% diffuse/patchy for CPA1 and 7.5% for REG1a), with a P-value of <0.0001 for both CPA1 and REG1a. The sensitivity and specificity of diffuse/patchy staining for CPA1 and REG1a in diagnosing pancreatic ACC/MANC were 100% and 95% for CPA1 and 84% and 93% for REG1a, respectively. In conclusion, CPA1 and REG1a are sensitive markers for ACC that can be used as additional acinar cell differentiation markers to help in the diagnosis of pancreatic ACC and MANC. A negative result for CPA1 virtually excludes ACC/MANC.

Paraneoplastic Cast Nephropathy Associated With Pancreatic Mixed Acinar-Neuroendocrine Carcinoma: A Case Report

Acute kidney injury is common in patients with cancer and may result from sepsis, obstruction, radiotherapy, chemotherapeutic agents, and nonsteroidal anti-inflammatory drugs. Rare reports of acute kidney injury due to cast nephropathy in patients with pancreatic acinar cell carcinoma have been described, but a pathogenetic link between cast nephropathy and carcinoma was not established. We report a patient with pancreatic mixed acinar-neuroendocrine carcinoma who developed severe acute kidney injury. Kidney biopsy showed cast nephropathy characterized by fractured periodic acid-Schiff-negative casts, associated with mononuclear and giant cell reaction. The patient did not have multiple myeloma and casts did not show immunoglobulin light chain restriction on immunofluorescence. Analysis using liquid chromatography-tandem mass spectrometry and immunohistochemistry identified 2 acinar cell-specific proteins, regenerating islet-derived 1α and carboxypeptidase A1, in both tubular casts and tumor cells. Thus, this case demonstrates that solid tumor-specific proteins can be nephropathic by obstructing renal tubules, resulting in acute kidney injury, a previously proposed but not characterized pathophysiologic mechanism for paraneoplastic nephropathy associated with carcinoma.

Conversion surgery for gastric cancer patients: A review

Gastric cancer (GC) is the third most common cancer-related cause of death worldwide. In locally advanced tumors, neoadjuvant chemotherapy has recently been introduced in most international Western guidelines. For metastatic and unresectable disease, there is still debate regarding correct management and the role of surgery. The standard approach for stage IV GC is palliative chemotherapy. Over the last decade, an increasing number of M1 patients who responded to palliative regimens of induction chemotherapy have been subsequently undergone surgery with curative intent. The objective of the present review is to analyze the literature regarding this approach, known as “conversion surgery”, which has become one of the most commonly adopted therapeutic options. It is defined as a treatment aiming at an R0 resection after chemotherapy in initially unresectable tumors. The 13 retrospective studies analyzed, with a total of 411 patients treated with conversion therapy, clearly show that even if standardization of unresectable and metastatic criteria, post-chemotherapy resectability evaluation and timing of surgery has not yet been established, an R0 surgery after induction chemotherapy with partial or complete response seems to offer superior survival results than chemotherapy alone. Additional larger sample-size randomized control trials are needed to identify subgroups of well-stratified patients who could benefit from this multimodal approach.

Effect of REG Iα protein on angiogenesis in gastric cancer tissues

Regenerating gene (REG) Iα is not only overexpressed in a subset of gastric cancers, but also involved in tumor progression. However, the mechanism by which (REG) Iα promotes tumor growth is not fully understood. In the present study, we investigated whether REG Iα plays a role in angiogenesis during the progression of gastric cancers. Expression of REG Iα and its receptor (EXTL3; exostoses like-3) was examined using immunohistochemistry in specimens of human gastric cancer. Microvessel density (MVD) in gastric cancer tissues was evaluated using an image analysis system after CD34 immunostaining. Relationships among clinicopathological features, REG Iα expression and MVD in gastric cancer tissues were analyzed. Effects of REG Iα protein on HUVEC cells in terms of proliferation and anti-apoptosis were assessed by WST-1 assay and FACS, respectively. Furthermore, the intracellular signaling by which REG Iα exerts its biological roles was examined in vitro. REG Iα expression was significantly related to lymph node metastasis and its receptor EXTL3 was ubiquitously expressed in not only the tumor cells, but also the tumor vessel cells in the gastric cancer tissues. MVD was significantly higher in gastric cancers that were REG Iα-positive than in those that were negative. Treatment with REG Iα protein promoted growth and anti-apoptosis through activation of the ERK and Akt signaling pathways in HUVEC cells, whereas these effects were attenuated by treatment with anti-REG Iα -antibody. REG Iα protein may play a role in angiogenesis during progression of gastric cancer.

Proteomic and metabolic prediction of response to therapy in gastric cancer

Several new treatment options for gastric cancer have been introduced but the prognosis of patients diagnosed with gastric cancer is still poor. Disease prognosis could be improved for high-risk individuals by implementing earlier screenings. Because many patients are asymptomatic during the early stages of gastric cancer, the diagnosis is often delayed and patients present with unresectable locally advanced or metastatic disease. Cytotoxic treatment has been shown to prolong survival in general, but not all patients are responders. The application of targeted therapies and multimodal treatment has improved prognosis for those with advanced disease. However, these new therapeutic strategies do not uniformly benefit all patients. Predicting whether patients will respond to specific therapies would be of particular value and would allow for stratifying patients for personalized treatment strategies. Metabolic imaging by positron emission tomography was the first technique with the potential to predict the response of esophago-gastric cancer to neoadjuvant therapy. Exploring and validating tissue-based biomarkers are ongoing processes. In this review, we discuss the status of several targeted therapies for gastric cancer, as well as proteomic and metabolic methods for investigating biomarkers for therapy response prediction in gastric cancer.

Diabetes mellitus increases the risk of early gastric cancer development

BACKGROUND

The significance of diabetes mellitus (DM) in gastric carcinogenesis still remains unclear. We investigated whether DM would be a risk factor for the development of early gastric cancer.

METHODS

Factors related to the presence of gastric cancer were examined in patients undergoing medical health checkups. We then investigated whether DM was related to the development of early gastric cancer during an endoscopic follow-up study.

RESULTS

Gastric cancer was detected in 14 (1.0%) of 1463 patients at the first endoscopic examination and was significantly associated with the severity of gastric atrophy and the presence of DM. During the follow-up period (range 36-108 months; mean 70.0 months), early gastric cancer was newly detected in 26 (1.8%) of the 1449 patients in whom gastric cancer had not been detected at the first examination. Gastric cancer was detected in 17 (1.3%) of 1301 patients without DM, and in 9 (6.1%) of 148 patients with DM (P < 0.0001). Multivariate analyses demonstrated that open-type gastric atrophy and DM were independently related to the development of early gastric cancer (P < 0.0001 and P = 0.020, respectively). Gastric cancer was identified in 14 (5.1%) of 274 patients who had open-type atrophic gastritis without DM, whereas it was identified in 8 (16.0%) of 50 patients who had both open-type atrophic gastritis and DM (P = 0.0042).

CONCLUSION

DM increases the risk of early gastric cancer development.

Gastric xanthelasma may be a warning sign for the presence of early gastric cancer

BACKGROUND AND AIM

The significance of gastric xanthelasma in relation to gastric disease still remains unclear. We investigated the prevalence and significance of gastric xanthelasma in patients with atrophic gastritis and gastric cancer.

METHODS

A total of 3238 patients who underwent endoscopic examinations of the upper gastrointestinal tract were enrolled. We retrospectively investigated the presence of gastric xanthelasma, the severity of gastric atrophy, and the presence of gastric cancer, and examined the relationship between gastric xanthelasma and various clinicopathological features.

RESULTS

Gastric xanthelasma was detected in 249 (7.7%) of the 3238 patients and was significantly associated with age ≥ 65 years, male gender, open-type atrophy, and the presence of gastric cancer (P < 0.0001, P = 0.0002, P < 0.0001 and P < 0.0001, respectively). Multivariate analysis revealed that the presence of gastric cancer was independently related to the presence of gastric xanthelasma (odds ratio 6.19 [3.95-9.70], P < 0.0001). Age/sex/atrophy-matched control analysis demonstrated that the presence of gastric xanthelasma was significantly associated with the presence of gastric cancer (P < 0.0001). Moreover, the presence of xanthelasma in the upper region of the stomach was significantly associated with gastric cancer (P = 0.002). Gastric xanthelasma was observed in 50 (47.6%) of 105 patients with gastric cancer.

CONCLUSION

Gastric xanthelasma may serve as a warning sign for the presence of gastric cancer.

S-1 (Teysuno®): a review of its use in advanced gastric cancer in non-Asian populations

S-1 (Teysuno(®)) is an oral anticancer agent comprising the 5-fluorouracil (5-FU) prodrug tegafur and targeted modulators, gimeracil and oteracil. S-1 in combination with cisplatin is a recommended first-line treatment for gastrointestinal cancers in Japan and has recently been approved in the EU for the treatment of advanced gastric cancer. This article reviews S-1 pharmacology from an EU perspective. In a randomized, open-label trial in 24 non-Asian countries in patients with advanced gastric cancer, there were no significant differences between S-1 plus cisplatin and 5-FU plus cisplatin groups in median overall survival (OS) [primary endpoint], progression-free survival or overall response rate. In a post hoc analysis of OS, S-1 plus cisplatin was noninferior to 5-FU plus cisplatin. There were no significant between-group differences in patient quality of life, according to the Functional Assessment of Cancer Therapy (Gastric) Trial Outcome Index, except that S-1 plus cisplatin recipients had a significantly longer time to worsening in physical well-being than 5-FU plus cisplatin recipients. Overall, S-1 plus cisplatin was better tolerated than 5-FU plus cisplatin, with significantly lower rates of haematological, some gastrointestinal tract and other adverse events, serious adverse events and deaths resulting from toxicity, along with significantly fewer haematological and renal function abnormalities. Compared with 5-FU, S-1 plus cisplatin recipients had significantly higher rates of hand-foot syndrome and hyperbilirubinaemia, although there were no between-group differences in the proportions of patients with increased liver enzymes. S-1 is a useful alternative to 5-FU for patients with advanced gastric cancer.