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

Genomic and genetic alterations influence the progression of gastric cancer

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, although the incidence has gradually decreased in many Western countries. Two main gastric cancer histotypes, intestinal and diffuse, are recognised. Although most of the described genetic alterations have been observed in both types, different genetic pathways have been hypothesized. Genetic and epigenetic events, including 1q loss of heterozygosity (LOH), microsatellite instability and hypermethylation, have mostly been reported in intestinal-type gastric carcinoma and its precursor lesions, whereas 17p LOH, mutation or loss of E-cadherin are more often implicated in the development of diffuse-type gastric cancer. In this review, we summarize the sometimes contradictory findings regarding those markers which influence the progression of gastric adenocarcinoma.

Clinical impact of aneuploidy on gastric cancer patients

Gastric cancer is a leading cause of death worldwide. Nowadays, complete surgical resection and TNM at diagnosis are the main prognostic factors. In spite of this, many patients will have a recurrence after surgery and die within a few months or years. That means that we need more accurate prognostic factors to design specific approaches for individual patients. Chromosome instability is a feature of gastric cancer commonly associated to chromosomal aberrations that leads to major modifications of DNA content globally termed as aneuploidy. In this regard, many authors' opinions diverge regarding the clinical impact of aneuploidy. This review will summarise data on the clinical impact of aneuploidy on clinical practice, the biological mechanisms that underlie chromosomal instability that induces aneuploidy and the relevance of specific chromosomal aneuploidy to cancer biology.

Flow cytometric cell cycle analysis allows for rapid screening of estrogenicity in MCF-7 breast cancer cells

The quantitative measurement of individual cells and their characteristics by means of flow cytometry is already for many years of great value for clinical studies. However, its potential as a tool in (eco)toxicology has only recently been discovered. Analysis of cell cycle kinetics with DNA-staining dyes can offer a valuable alternative to detect effects of chemicals on cell proliferation, an important endpoint in screening estrogen-like properties of chemicals. In the present study, flow cytometric cell cycle analysis in growth arrested MCF-7 cells exposed to five xenoestrogens correspond well with cell proliferation results of the conventionally used E-screen assay. Moreover, re-induction of proliferation in MCF-7 cells, indicated by the percentage of cells in S(ynthesis)-phase, is most pronounced after 24 h exposure, thus allowing a faster screening of xenoestrogens. This flow cytometric proliferation assay confirms that the estrogenic activity of structurally analogous parabens is mediated by the estrogen receptor pathway and is proportional to the alkyl chain length. Moreover, the ER-mediated mode of action of two fluorotelomer alcohols (6:2 FTOH and 8:2 FTOH), recently reported as xenoestrogenic, could be elucidated. These results support the potential of flow cytometric cell cycle kinetics as a screening assay for estrogen-like properties of chemicals.

DNA ploidy and its clinical implications in gastric cancer

BACKGROUND

Biological characteristics of gastric cancer depend mostly on genetic alterations in the cancer cells of individuals. To precisely predict the biological behavior and clinical outcome of individual cancer, it may be important to clarify the DNA profiles of cancer cells in each case.

METHODS

We have reviewed the most important results of studies on DNA ploidy of gastric cancer published in the English literature during the last 2 decades.

RESULTS

Gastric carcinoma with aneuploidy has been shown to have a high proliferative activity and a high metastatic or invasive potential, thus leading to a poor prognosis as compared to diploid tumors.

CONCLUSION

Analyses of DNA ploidy in gastric cancer may provide clinically useful information on diagnostic, therapeutic, and prognostic aspects. Further investigations may be needed to clarify the relationship between chromosome instability and DNA ploidy.

A prospective correlation of Laurén's histological classification of stomach cancer with clinicopathological findings including DNA flow cytometry

Between November 1990 and December 1992, 217 patients with stomach cancer were enrolled in a prospective study evaluating the prognostic value of DNA flow cytometry. Laurén's histological type was evaluated in 216 cases, of which 102 (47%) were of the diffuse type, 74 (34%) were of the intestinal type, and 40 (19%) were mixed type tumors. Laurén's histological type showed a significant correlation with age (p = 0.028), sex (p = 0.004), tumor size (p = 0.002), T stage (p = 0.006), overall TNM stage (p = 0.008), histological grade (p < 0.001), and tumor ploidy (p < 0.001). Intestinal type stomach cancer showed a significantly higher proportion of aneuploidy [diffuse vs. intestinal type; 41/102 (40%) vs. 52/74 (70%)]. After a median follow-up of 66.1 months (range, 29.6-78.1), 110 of 216 patients (51%) survived. Patients with intestinal type stomach cancer had a significantly better survival than did those with diffuse type stomach cancer (64% vs. 42% of patients surviving, p = 0.020). Our study suggests that there are biological differences between the two subtypes of Laurén's classification of stomach cancer in addition to the morphological differences. Laurén's classification should remain valid in future studies investigating the pathogenetic and clinical aspects of stomach cancer.

DNA aneuploidy and high proliferative activity but not K-ras-2 mutations as independent predictors of clinical outcome in operable gastric carcinoma: results of a 5-year Gruppo Oncologico dell'Italia Meridonale (GDIM) prospective study

BACKGROUND

The prognostic value of DNA ploidy, S-phase fraction (SPF) and K-ras-2 mutations in gastric carcinoma (GC) has not yet been clearly defined. The aim of this study was to clarify the association between biomolecular variables, tumor characteristics, and clinical outcome in GC patients.

METHODS

Resected specimens from a consecutive series of 69 patients with GC who underwent potentially curative surgery were studied prospectively. DNA ploidy and SPF were assessed by flow cytometry on multiple frozen tumor samples, whereas K-ras-2 mutations were detected by polymerase chain reaction followed by single-strand conformation polymorphism. All the patients involved in this study were followed up for a mean of 95 months.

RESULTS

DNA aneuploidy was present in 72% of the cases (50 of 69), whereas 10% of these (5 out of 50) showed multiclonality. Mutations of K-ras-2 were detected in 8% of the tumors (5 of 63). Both DNA ploidy and SPF were associated with TNM stage (American Joint Committee on Cancer [AJCC] staging system) and node status. Moreover, DNA aneuploidy was significantly related to high SPF. K-ras-2 mutations were not associated with clinicopathologic variables or flow cytometric indicators. At univariate analysis, advanced TNM stage, node involvement, diffuse histotype, depth of invasion, DNA aneuploidy, and high SPF proved to be significantly related to quicker tumor relapse and to shorter overall patient survival. With multivariate analysis, DNA aneuploidy, high SPF, and depth of invasion were related to risk of tumor relapse and patient death, whereas diffuse histotype was independently related to patient risk of tumor relapse.

CONCLUSIONS

DNA ploidy and SPF, when associated with clinicopathologic staging, might be useful for the identification of GC patients who have different risks for death or relapse of disease.