The prognostic determinants of gastric cancer treatment outcome in Omani Arab patients

The first Middle East and North Africa expert consensus recommendations for management of advanced gastric cancer

Gastric cancer (GC) ranks as the fifth most prevalent cancer and the fourth deadliest cancer worldwide. In the Middle East and North Africa (MENA) region, GC represents about 4.8% of cancer cases with more than 35,000 new cases in 2020. To strengthen and improve the management of this cancer in the region, a group of MENA experts in the field of GC developed the first MENA consensus recommendations for the management of advanced GC. A total of 28 statements were drafted, discussed and voted on, using a modified Delphi process, during a virtual consensus meeting. The statements addressed the areas of epidemiology, biomarkers and treatment.

An emphasis on the interaction of signaling pathways highlights the role of miRNAs in the etiology and treatment resistance of gastric cancer

Gastric cancer (GC) is 4th in incidence and mortality rates globally. Several genetic and epigenetic factors, including microRNAs (miRNAs), affect its initiation and progression. miRNAs are short chains of nucleic acids that can regulate several cellular processes by controlling their gene expression. So, dysregulation of miRNAs expressions is associated with GC initiation, progression, invasion capacity, apoptosis evasions, angiogenesis, promotion and EMT enhancement. Of important pathways in GC and controlled by miRNAs are Wnt/β-catenin signaling, HMGA2/mTOR/P-gp, PI3K/AKT/c-Myc, VEGFR and TGFb signaling. Hence, this review was conducted to review an updated view of the role of miRNAs in GC pathogenesis and their modulatory effects on responses to different GC treatment modalities.

BRCA1/BRCA2 mutation spectrum analysis in South Asia: a systematic review

Objective

Breast cancer (BC) is the most common form of cancer among Asian females. Mutations in the BRCA1/BRCA2 genes are often observed in BC cases and largely increase the lifetime risk of having BC. Because of the paucity of high-quality data on the molecular spectrum of BRCA mutations in South Asian populations, we aimed to explore these mutations among South Asian countries.

Methods

A systematic literature search was performed for the BRCA1 and BRCA2 gene mutation spectrum using electronic databases such as PubMed, EMBASE, and Google Scholar. Twenty studies were selected based on specific inclusion and exclusion criteria.

Results

The 185delAG (c.68_69del) mutation in exon 2 of BRCA1 was the most common recurrent mutation and founder mutation found. Various intronic variants, variants of unknown significance, large genomic rearrangements, and polymorphisms were also described in some studies.

Conclusions

The South Asian population has a wide variety of genetic mutations of BRCA1 and BRCA2 that differ according to countries and ethnicities. A stronger knowledge of various population-specific mutations in these cancer susceptibility genes can help provide efficient strategies for genetic testing.

Current status and scope of lymph node micrometastasis in gastric cancer

Recently, lymph node micrometastasis has been evaluated for its prognostic value in gastric cancer. Lymph node micrometastasis cannot be detected via a usual pathologic examination, but it can be detected by using some other techniques including immunohistochemistry and reverse transcription-polymerase chain reaction assay. With the development of such diagnostic techniques, the detection rate of lymph node micrometastasis is constantly increasing. Although the prognostic value of lymph node micrometastasis remains debatable, its clinical impact is apparently remarkable in both early and advanced gastric cancer. At present, studies on the prognostic value of lymph node micrometastasis are evolving to overcome its current limitations and extend the scope of its application.

Gastric carcinoma: stage migration by immunohistochemically detected lymph node micrometastases

BACKGROUND

Immunohistochemically detected micrometastases of the regional lymph nodes in previously pN0-classified gastric cancer have been incorporated in the TNM staging system. This study aims to determine the incidence of such micrometastases in gastric carcinoma and to investigate their impact on stage grouping and prognosis.

METHODS

Ninety-five patients with gastric carcinoma classified as pN0 by conventional histological examination were enrolled. All patients underwent gastric resection with regional lymphadenectomy between 2006 and 2010. A total of 2018 lymph nodes was obtained (median, 20 Lymph nodes) and immunohistostained with anti-pan cytokeratin antibody (KL1).

RESULTS

Micrometastases were detected in regional lymph nodes by immunohistostaining in 16 out of all 95 patients. Fourteen patients were upstaged by micrometastasis-positive regional lymph nodes. Three patients demonstrated lymph nodes with isolated tumor cells alone. A significantly higher incidence of micrometastases was observed in patients with diffuse histologic type (p = 0.007) and total gastrectomy (p = 0.007). When isolated tumor cells were also regarded as lymph node involvement, the recurrence rate was significantly higher for node-positive than for node-negative patients and for those younger than 70 years (33.3 and 6.7 %, respectively; p = 0.026; n = 39). Overall survival analysis revealed no significant difference between micrometastasis-positive and micrometastasis-negative patients.

CONCLUSION

Immunohistostaining of regional lymph nodes in node-negative gastric carcinoma patients leads to an increased detection of micrometastases with significant implications for the staging system. Although no impact on survival time was shown, the higher recurrence rate for node-positive patients younger than 70 years indicates a prognostic value of immunohistochemically detectable micrometastases.

Detection and clinical significance of lymph node micrometastasis in gastric cardia adenocarcinoma

OBJECTIVES

Lymph node micro metastasis was investigated in gastric cardia adenocarcinoma (GCA) patients without lymph node metastasis on routine pathological examination. The relationship between micrometastasis and clinicopathological features was also evaluated.

METHODS

A total of 349 lymph nodes were obtained from 45 patients with GCA. Micrometastases were detected by immunohistochemical staining for the markers cytokeratin 19 (CK19) and CD44 variant 6 (CD44v6).

RESULTS

A total of 33 lymph nodes (9.5%) from 15 patients (33.3%) were positive for CK19. Of these, 27 lymph nodes (7.7%) from 12 patients (26.7%) were also positive for CD44v6. Micrometastasis was significantly related to depth of tumour invasion and Lauren classification (intestinal or diffuse). The recurrence rate was significantly higher and 2-year survival rate significantly lower in patients with than in those without lymph node micrometastasis, showing the necessity of detecting micrometastasis in GCA patients who test negative for lymph node metastasis on routine examination.

CONCLUSION

CK19 and CD44v6 were shown to be good markers for micrometastasis detection.

Gastric cancer risk predisposition and prognostic significance of vascular endothelial growth factor (VEGF) gene polymorphisms--a case-control study in an Omani population

Vascular endothelial growth factor (VEGF) plays a central role in angiogenesis, tumor growth, and metastasis. We investigated the associations between VEGF gene polymorphisms and gastric cancer (GC) risk predisposition and prognostic characteristics in an Omani population, an ethnic group which has not been studied previously. We analyzed three VEGF polymorphisms (+405 G/C, -460 T/C, and +936 C/T) by the extraction of genomic DNA from peripheral blood of 130 GC patients and 130 control subjects followed by VEGF genotyping using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. There were no significant associations between the VEGF polymorphisms and GC risk. There were significant correlations between the +405 C/C genotype and both poor tumor differentiation (P = 0.007) and lymph node metastasis (P = 0.03) and between the -460 T/T genotype and poor tumor differentiation (P = 0.03) with a statistical trend toward lymph node involvement (P = 0.05). VEGF gene polymorphisms had no significant effects on survival, but the VEGF +405 G/G genotype had a statistical trend toward lower survival rate with a hazard ratio of 1.6 [95% CI, 0.9-2.9] compared with the VEGF +405 CC/GC combined genotype (P = 0.049). Multivariate analysis showed that disease stage at diagnosis and the +405 G/G genotype were independent variables of adverse prognostic significance. There were no associations between the six common haplotypes identified and both GC risk predisposition and survival. The current study suggests that VEGF polymorphisms have no role in GC risk predisposition, but may have prognostic significance in GC patients.

Measurement of circulating levels of VEGF-A, -C, and -D and their receptors, VEGFR-1 and -2 in gastric adenocarcinoma

AIM: To analyze the serum levels and prognostic significance of vascular endothelial growth factor (VEGF) -A, -C, and -D, and their receptors, VEGFR-1 and -2 in gastric adenocarcinomas.

METHODS: The serum levels of VEGF family members were measured in 76 control subjects and 76 patients with gastric adenocarcinoma using an enzyme-linked immunosorbent assay (ELISA). These measurements were correlated with clinco-pathological features and survival rates.

RESULTS: The serum levels of VEGF-A and its receptor, VEGFR-1, were significantly higher in patients with gastric cancer than in healthy donors (t = 2.3, P = 0.02 and t = 4.2, P < 0.0001, respectively). In contrast, the serum levels of VEGF-D were significantly higher in control subjects than in patients (t = 2.9, P = 0.004). There was no significant difference in serum levels of VEGF-C and VEGFR-2 between patients and controls. VEGF-C was associated with advanced tumor stage and presence of metastasis. VEGFR-1 was associated with metastasis, advanced overall stage, tumor differentiation and survival. VEGFR-2 levels were associated with poor tumor differentiation. There was no significant prognostic value for any of the VEGF family members or their receptors except for VEGFR-1 where high levels were associated with a poor overall survival.

CONCLUSION: Serum VEGF levels vary significantly in the same cohort of patients with variable clinico-pathological features and prognostic values. The simultaneous measurement of VEGF receptors levels in sera may overcome the limitations of a single biomarker assay.

Effect of lymph node micrometastases on prognosis of gastric carcinoma

AIM: To evaluate the relationship between lymph node micrometastases and prognosis of patients with gastric carcinoma and to evaluate the significance of the new assessment of nodal status in determining the pN categories in the 5th edition of the UICC TNM classification.

METHODS: A total of 850 lymph nodes from 30 patients with gastric carcinoma who underwent gastrectomy with lymphadenectomy were assessed by reverse transcription polymerase chain reaction assay in addition to histologic examination. Cytokeratin-20 gene marker was used in this assay.

RESULTS: Routine examination by HE staining confirmed metastasis in 233 lymph nodes from 20 patients. All these 233 lymph nodes were cytokeratin-20 positive. Moreover, lymph node micrometastases were detected in an additional 67 lymph nodes in 12 of these 20 patients. Lymph node micrometastases were also detected in 10 lymph nodes from 2 of 10 patients who had no obvious metastases identified by HE staining. Totally, lymph node micrometastases were identified by the reverse transcription polymerase chain reaction assay in 77 (12.5%) lymph nodes from 14 (46.7%) patients with gastric carcinoma. Of 27 patients who underwent curative resection, 7 (25.9%) were up-staged (fromIB stage to II stage in 1 patient, from IB stage to IIIA stage in 1 patient, from II stage to IIIA stage in 1 patient, from IIIA stage to IIIB stage in 1 patient, from IIIA stage to IV stage in 1 patient, from IIIB stage to IV stage in 2 patients). In a median follow-up of 32 (range 8-36) mo, Kaplan-Meier survival analysis showed significant improvements in median survival (22.86 ± 3.17 mo, 95% CI: 16.64-29.08 mo vs 18.00 ± 7.4 mo, 95% CI: 3.33-32.67 mo) of patients with negative lymph node micrometastases over patients with positive lymph node micrometastases (log-rank, P < 0.05).

CONCLUSION: Lymph node micrometastases have a significant impact on the current staging system of gastric carcinoma, and are significant risk factors for prognosis of patients with gastric carcinoma.