DNA aneuploidy in gastric carcinoma. Flow cytometric data related to survival, location, and histopathologic findings

Prognostic value of DNA aneuploidy in gastric cancer: a meta-analysis of 3449 cases

Background

DNA aneuploidy has attracted growing interest in clinical practice. Nevertheless, its prognostic value in gastric cancer patients remains controversial. This meta-analysis aims to explore the impact of DNA ploidy status on the survival of gastric cancer patients.

Methods

We used PubMed and Web of Science databases to retrieve relevant articles. The correlation between DNA aneuploidy and the clinicopathological features of gastric cancer, such as stage, depth of invasion (T), lymph node metastasis (N), distant metastasis (M), differentiation (G), tumor types (Lauren classification) and overall survival (OS) were evaluated. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were collected carefully from each article OS was presented with HRs. The relationships between DNA aneuploidy and each characteristic were analyzed using risk ratios (RR) and a 95% confidence interval (CI). Significance was established using P < 0.05. Funnel plot was conducted to detect the publication bias.

Results

After careful selection, 25 studies involving 3449 cases were eligible for further analyses. Patients with DNA aneuploidy were considered at risk of more advanced stages (stage III-IV vs. stages I-II, RR = 1.23; 95% CI, 1.07 to 1.42; P = 0.003), lymph node metastasis (N+ vs. N-: RR = 1.43; 95% CI, 1.12 to 1.82, P = 0.004), and intestinal tumor type (intestinal vs. diffuse: RR = 1.45; 95% CI, 1.02 to 2.06; P = 0.04). And an adverse relation was observed between DNA aneuploidy and tumor differentiation. While no association was found between DNA aneuploidy and distant metastasis (P = 0.42) nor depth of tumor invasion (P = 0.86). Regarding overall survival, aneuploid tumors were associated with worse survival in all patients (P < 0.00001).

Conclusions

We found that DNA aneuploidy was an important predictor for gastric cancer patients, and should be used as a potential biomarker for further classification in gastric cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5869-9) contains supplementary material, which is available to authorized users.

Clinical aspect and molecular mechanism of DNA aneuploidy in gastric cancers

The biological characteristics of cancers depend mostly on genetic alterations in the cancer cells of individuals. Gastric cancers show a high frequency of DNA aneuploidy, a phenotype of chromosomal instability. Compared to diploid tumors, gastric carcinomas with aneuploidy have been shown to have high proliferative activity and high metastatic or invasive potential; these characteristics lead to a poor prognosis. It has been suggested that an abnormal spindle assembly checkpoint is involved in DNA aneuploidy, but the underlying mechanism is still unclear. This review, in order to determine whether gastric carcinomas that display aneuploidy are associated with a poorer prognosis than diploid tumors, and to discuss the biological mechanisms that induce aneuploidy, summarizes the results of studies on DNA ploidy in gastric cancer published in the English literature. Analysis of DNA ploidy in gastric cancer may provide clinically useful information from diagnostic, therapeutic, and prognostic standpoints. Further investigations may be needed to clarify the relationship between chromosome instability and DNA ploidy.

Checkpoint with forkhead-associated and ring finger promoter hypermethylation correlates with microsatellite instability in gastric cancer

AIM: To examine the methylation status of the promoter region of the checkpoint with forkhead-associated and ring finger (CHFR) and microsatellite mutator status in 59 primary gastric cancers.

METHODS: We investigated the promoter methylation of CHFR in 59 cases of gastric cancer using methylation-specific PCR. Five microsatellite loci were analyzed using high-intensity microsatellite analysis reported previously, and p53 gene mutations were investigated by direct sequencing.

RESULTS: Twenty cases (33.9%) showed promoter methylation and no relation was observed with the clinicopathological factors. We found that the promoter methylation of CHFR was frequently accompanied with microsatellite instability (MIN). Seven of 20 (35.0%) cases showed MIN in hypermethylation of the CHFR tumor, while three of 39 (7.7%) cases showed MIN in the non-methylated CHFR tumor (P < 0.01). However, we failed to find any relationship between CHFR methylation and p53 mutation status.

CONCLUSION: The coordinated loss of both the mitotic check point function and mismatch repair system suggests the potential to overcome the cell cycle check point, which may lead to an accumulation of mutations. However, the p53 mutation was not related to hypermethylation of the CHFR promoter and MIN, which indicates that an abnormality in p53 occurs as an independent process from the mismatch repair deficiency in carcinogenesis.

Flow cytometric DNA ploidy, p53, PCNA, and c-erbB-2 protein expressions as predictors of survival in surgically resected gastric cancer patients

In order to determine retrospectively the impact of some cytometric and immunohistochemical parameters on the overall survival of gastric cancer patients treated with surgery alone, paraffin-embedded tumor samples from 137 gastric carcinoma patients undergoing curative resection from 1987-1993 were analyzed by flow cytometry (FCM) and immunohistochemistry (p53, c-erbB-2, and PCNA expression). FCM-derived parameters were DNA ploidy and fraction of S-phase cells (SPF). Multiple regression analysis was applied to determine the prognostic significance of the conventional clinicopathologic findings together with the flow cytometric and immunohistochemical parameters on overall survival. When all parameters were entered simultaneously into the Cox regression model, stage and DNA ploidy (DNA index >1.35) clearly emerged as the only independent prognostic factors. When the stages were analysed separately, the independent prognostic factors resulted DNA ploidy in early stages (I-II) and grading in stage IIIA tumors. For stage IIIB tumors, no independent prognostic factor was found. These results indicate that the DNA ploidy pattern is a valuable predictor of survival in curatively resected gastric cancer patients, especially when less advanced tumors are taken into consideration.

Prognostic value of DNA flow cytometry in stomach cancer: a 5-year prospective study

The role of DNA flow cytometry in the prediction of prognosis for patients with stomach cancer remains to be defined. Thus we studied prospectively the role of DNA flow cytometry as a prognosis indicator in stomach cancer patients in a high-incidence area. Between November 1990 and December 1992, primary stomach cancer tissues were obtained from the surgical specimens from 217 patients (148 male, 69 female). DNA flow cytometric analyses of DNA ploidy and S-phase fraction were performed and the results were correlated with patient survival. The median age of the patients was 55 years (range 24-78). Aneuploid cell population was found in 114 of 217 samples (53%). Tumour S-phase fraction was obtained in 96 of 103 diploid tumours (93%) and 61 of 114 aneuploid tumours (54%). After median follow-up of 66.1 months, the patients with tumours with an S-phase fraction over 17% had significantly worse survival rates than patients with tumours with S-phase fractions of lower than 8% or 8-17% (45% vs 59% and 63% of patients surviving, P = 0.007). Tumour ploidy status did not correlate with patient survival. Multivariate analyses showed that the TNM stage remained the most important prognostic indicator. The tumour S-phase fraction was also an independent prognostic indicator (relative risk 2.300, 95% CI, 1.252-4.223). Tumour S-phase fraction obtained by DNA flow cytometry is an independent prognostic indicator for the survival of the patients with stomach cancer.

DNA flow cytometry in gastric carcinoma: implication in patients with potentially curative resection

BACKGROUND AND OBJECTIVES

The relevance of DNA ploidy as a prognostic factor in patients with gastric cancer is controversial. The prognostic significance of DNA ploidy and its relationship to conventional histological grading and staging of the tumor (TNM stage, Lauren, Ming and WHO classification) were evaluated.

METHODS

DNA ploidy of the tumor was determined by flow cytometry on archival material from 76 patients who underwent R0, D2 stomach resection.

RESULTS

DNA aneuploidy was found in 39 cases (51%). No significant association between DNA aneuploidy and either patients' sex, pT, pN, type according to Ming or Borrmann and tumor localization was found. The incidence of DNA aneuploidy was significantly lower in tumors of diffuse type according to Lauren, in signet-ring cell or undifferentiated type (WHO), in grade 3/4 tumors, and in patients younger than 50 years. We found no significant difference in survival of patients with DNA aneuploid when compared to DNA diploid tumors, although the prognosis of the patients with lower DNA index (DI < 1.2) tended to be better than that of higher DNA index (DI > 1.2).

CONCLUSIONS

DNA ploidy appears to be of limited prognostic value after R0, D2 resection of stomach cancer.

DNA analysis by flow cytometry in early gastric cancer

OBJECTIVES

Flow cytometric analysis of a paraffin-embedded block of tissue provides rapid and accurate means of analyzing the DNA content of a tumor. The aim of this study was to clarify the clinical significance of flow cytometric findings in early gastric cancer(EGC). Thus we conducted this study to investigate whether DNA contents of tumor cells can correlate with known prognostic indices in patients with EGC.

METHODS

The flow cytometric DNA analysis was performed with paraffin-embedded specimens from tumors of 107 patients with EGC. Flow cytometric analysis was performed using a FACScan (Becton Dickinson). In constructing the histogram, 30,000 cells were scanned from each section and results were scored. The S-phase fraction was obtained according to the CellFit cell cycle analysis (Becton Dikinson). Frequencies of aneuploidy in tumors with various clinical and pathologic parameters were compared using the chi-square test. Mean SPF/PI valuse were compared by the student t-test.

RESULTS

Diploidy pattern was observed in 80 (75%) cases while aneuploidy was seen in 27(25%) cases. Aneuploidy was more frequently detected in tumors with submucosal involvement (32.7%) and lymph node (+) group (30.8%) than in the mucosal tumor (17.3%) and lymph node (-) group (24.5%), but the differences were not significant. Frequency of aneuploidy was not affected by either the histologic type or morphologic classification. On the other hand, high proliferative activities (SPF/PI) significantly correlated with the submucosal tumor invasion (66.7% vs. 45%; p < 0.05) and lymph node metastasis (28.6% vs. 7.5%; p < 0.05).

CONCLUSION

Tumor aggressiveness is not directly related to DNA aneuploidy but proliferative activities are responsible for the aggressive nature of early gastric cancer. The results of this study show that DNA analysis by flow cytometry in considered to be one method of determining the biological activity of gastric cancer cells.