Histopathologic characteristics of gastric adenocarcinoma in Mexican patients: a 10-year experience at the Hospital Juárez of Mexico

Somatic Mutational Landscape in Mexican Patients: CDH1 Mutations and chr20q13.33 Amplifications Are Associated with Diffuse-Type Gastric Adenocarcinoma

The Hispanic population, compared with other ethnic groups, presents a more aggressive gastric cancer phenotype with higher frequency of diffuse-type gastric adenocarcinoma (GA); this could be related to the mutational landscape of GA in these patients. Using whole-exome sequencing, we sought to present the mutational landscape of GA from 50 Mexican patients who were treated at The Instituto Nacional de Cancerología from 2019 to 2020. We performed a comprehensive statistical analysis to explore the relationship of the genomic variants and clinical data such as tumor histology and presence of signet-ring cell, H. pylori, and EBV. We describe a potentially different mutational landscape between diffuse and intestinal GA in Mexican patients. Patients with intestinal-type GA tended to present a higher frequency of NOTCH1 mutations, copy number gains in cytobands 13.14, 10q23.33, and 12q25.1, and copy number losses in cytobands 7p12, 14q24.2, and 11q13.1; whereas patients with diffuse-type GA tended to present a high frequency of CDH1 mutations and CNV gains in cytobands 20q13.33 and 22q11.21. This is the first description of a mutational landscape of GA in Mexican patients to better understand tumorigenesis in Hispanic patients and lay the groundwork for discovering potential biomarkers and therapeutic targets.

Nutritional Indexes as Predictors of Survival and Their Genomic Implications in Gastric Cancer Patients

Gastric cancer is an aggressive malignancy with poor prognosis. Although obesity is a risk factor, an association between overweight and better survival has been reported. We explored the genomic implications of such association. Data from 940 patients were analyzed using Cox regression models and ROC curves to assess body mass index (BMI) and prognostic nutritional index (PNI) as predictors of survival. The exome sequencing of a random subset was analyzed to determine copy number variation (CNV) and single nucleotide variation (SNV), using Kruskal-Wallis and chi-square tests to evaluate their clinical implications. Overall survival was lower in patients with BMI ≤ 24.9 and PNI ≤ 29 (p < 0.001). BMI and survival were directly correlated (HR: 0.972, 95% CI: 0.953, 0.992; p-value < 0.007). A higher PNI correlated with improved survival (HR: 0.586, 95% CI: 0.429, 0.801; p-value <0.001). We found a PNI cutoff point of 41.00 for overall survival. Genomic analysis showed an association between lower BMI, less CNV events (p-value = 0.040) and loss of tumor suppressor genes (p-value = 0.021). BMI and PNI are independent factors for overall survival in gastric cancer, probably linked to variations in genomic intratumoral alterations.

The Mexican consensus on the detection and treatment of early gastric cancer

Gastric cancer is one of the most frequent neoplasias in the digestive tract and is the result of premalignant lesion progression in the majority of cases. Opportune detection of those lesions is relevant, given that timely treatment offers the possibility of cure. There is no consensus in Mexico on the early detection of gastric cancer, and therefore, the Asociación Mexicana de Gastroenterología brought together a group of experts and produced the "Mexican consensus on the detection and treatment of early gastric cancer" to establish useful recommendations for the medical community. The Delphi methodology was employed, and 38 recommendations related to early gastric cancer were formulated. The consensus defines early gastric cancer as that which at diagnosis is limited to the mucosa and submucosa, irrespective of lymph node metástasis. In Mexico, as in other parts of the world, factors associated with early gastric cancer include Helicobacter pylori infection, a family history of the disease, smoking, and diet. Chromoendoscopy, magnification endoscopy, and equipment-based image-enhanced endoscopy are recommended for making the diagnosis, and accurate histopathologic diagnosis is invaluable for making therapeutic decisions. The endoscopic treatment of early gastric cancer, whether dissection or resection of the mucosa, should be preferred to surgical management, when similar oncologic cure results can be obtained. Endoscopic surveillance should be individualized.

Circulating blood levels of IL-6, IFN-γ, and IL-10 as potential diagnostic biomarkers in gastric cancer: a controlled study

Background

Gastric adenocarcinoma is the third most common cause of cancer-associated death worldwide. Helicobacter pylori infection activates a signaling cascade that induces production of cytokines and chemokines involved in the chronic inflammatory response that drives carcinogenesis. We evaluated circulating cytokines and chemokines as potential diagnostic biomarkers for gastric cancer.

Methods

We included 201 healthy controls and 162 patients with distal gastric cancer who underwent primary surgical resection between 2009 and 2012 in Mexico City. The clinical and pathological data of patients were recorded by questionnaire, and the cancer subtype was classified as intestinal or diffuse. Pathological staging of cancer was based on the tumor–node–metastasis staging system of the International Union Against Cancer. Concentrations of IL-1β, IL-6, TNF-α, IL-10, and MCP-1 in serum were measured using multiplex analyte profiling technology and concentrations of IL-8, IFN-γ, and TGF-β in plasma were measured using enzyme-linked immunosorbent assay.

Results

Levels of IL-1β, IL-6, IFN-γ, and IL-10 were significantly higher and that of MCP-1 was lower in gastric cancer patients compared with controls. No differences in IL-8 or TNF-α levels were observed between gastric cancer and controls. IFN-γ and IL-10 were significantly higher in both intestinal and diffuse gastric cancer, whereas IL-1β and IL-6 were higher and TGF-β lower only in intestinal gastric cancer; MCP-1 was lower only in diffuse gastric cancer. IFN-γ and IL-10 levels were significantly higher in early (I/II) and late stage (III/IV) gastric cancer; IL-1β and IL-8 were higher and MCP-1 was lower only in late stage (IV) patients. Receiver-operating characteristic analysis showed that for diagnosis of GC, IL-6 had high specificity (0.97) and low sensitivity (0.39), IL-10 had moderate specificity (0.82) and low sensitivity (0.48), and IL-1β and IFN-γ showed low specificity (0.43 and 0.53, respectively) and moderate sensitivity (0.76 and 0.71, respectively).

Conclusions

Increased levels of IL-6, IFN-γ, and IL-10 might be useful as diagnostic biomarkers for GC; however, this needs to be confirmed with larger number of patients and with control groups other than blood donors, properly age paired. IL-1β, IL-6, MCP-1, and TGF-β differentiate intestinal from diffuse GC. IFN-γ and IL-10 might be useful for diagnosis of early stage GC, and IL-1β, IL-8, and MCP-1 for late stages of the disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3310-9) contains supplementary material, which is available to authorized users.

Current approaches to gastric cancer in Peru and Mexico

In Peru, the incidence of gastric cancer is reported to be around 15.8 per 100,000 inhabitants and it is the second most common oncological disease in men and the third one in women. Additionally, a high mortality index was reported, especially among poor people. To address this issue, in 2008, Peru initiated several insurance treatment plans of oncological diseases with promising results. In Mexico, there is a high predominance of gastric cancer in male gender compared to female gender, even reaching a 2/1 ratio, and the detection rate of early gastric cancer is low (10% to 20%) which results in a mainly palliative treatment with an overall survival rate in 5 years about 10% to 15% only. In Peru, the average age at diagnosis is around 62.96±14.75 years old and the most frequent symptoms includes abdominal pain, indigestion, loss of appetite, weight loss and gastrointestinal bleeding, while in Mexico, some studies reported an average age at diagnosis around 60.3±4.1 years old (range, 23-78 years old) and the most frequent symptoms were postprandial fullness (74.4%), abdominal pain (37.2%), weight loss (18.6%), and melena (4.6%). The anemia rate was 65.1% with a mean Hb level of 6.14 g/dL. In Peru, the most common gastric cancer type is the intestinal-type adenocarcinoma (around 34%), followed by the diffuse-type adenocarcinoma (18.7%), whilst among Mexicans, the diffuse-type was reported in 55.2% of cases, the intestinal-type was reported in 28.2% and the undifferentiated-type corresponded to 6%. In both, Peru and Mexico, 90% of the associated factors includes tabaquismo, diets rich in salt, smoked foods, and a sedentary lifestyle. Family inheritance and advanced age and pharmacological-resistant Helicobacter pylori infection are also important. Poverty has been heavily associated with a higher incidence of gastric cancer. The management of gastric cancer patients in Peru is carried out by general surgeons or general surgical oncologists. In recent years, efforts have been made by the Peruvian government to establish specialized surgical centers which resulted in an improvement in morbidity and mortality rates, as well as an increase in the retrieval of lymph nodes. In Mexico, during the last 5 years, D1+ has been reported to be the most predominant lymphadenectomy-type, particularly in specialized surgical services. There have been a decrease in mortality rate from 7.5 per 100,000 inhabitants in 2000 to 5.6 per 1,000,000 inhabitants in 2012. Additional steps in order to continue improving gastric cancer management in Peru and Mexico are needed.