Clinical Relevance of Tumor Ploidy and Micronucleus Formation for Oral Cavity Cancer

Dietary reference values of individual micronutrients and nutriomes for genome damage prevention: current status and a road map to the future

Damage to the genome is recognized as a fundamental cause of developmental and degenerative diseases. Several micronutrients play an important role in protecting against DNA damage events generated through endogenous and exogenous factors by acting as cofactors or substrates for enzymes that detoxify genotoxins as well as enzymes involved in DNA repair, methylation, and synthesis. In addition, it is evident that either micronutrient deficiency or micronutrient excess can modify genome stability and that these effects may also depend on nutrient-nutrient and nutrient-gene interaction, which is affected by genotype. These observations have led to the emerging science of genome health nutrigenomics, which is based on the principle that DNA damage is a fundamental cause of disease that can be diagnosed and nutritionally prevented on an individual, genetic subgroup, or population basis. In this article, the following topics are discussed: 1) biomarkers used to study genome damage in humans and their validation, 2) evidence for the association of genome damage with developmental and degenerative disease, 3) current knowledge of micronutrients required for the maintenance of genome stability in humans, 4) the effect of nutrient-nutrient and nutrient-genotype interaction on DNA damage, and 5) strategies to determine dietary reference values of single micronutrients and micronutrient combinations (nutriomes) on the basis of DNA damage prevention. This article also identifies important knowledge gaps and future research directions required to shed light on these issues. The ultimate goal is to match the nutriome to the genome to optimize genome maintenance and to prevent pathologic amounts of DNA damage.

Ploidy study in oral carcinomas: use of improved methodology to assess its clinical prognostic value

OBJECTIVE

This study reports a ploidy analysis in oral squamous cell carcinomas (SCC) using methodologic adjustments to improve the accuracy of the measurements and derive numeric indices of aggressiveness of prognostic value.

STUDY DESIGN

Sixty-seven SCC were assessed by DNA image cytometry in the areas of the histologic sections with most atypia. Five indices of aggressiveness were analyzed in relation to the clinical-pathologic data and evolution of the patients.

RESULTS

The mean value of the index of deviation from the diploid value (2cDi) and malignancy index (Mi), taken as a cut-off value, defined 2 populations with statistically significant differences in survival. In patients with tumors in clinical stages III and IV (TNM classification), the Mi also exhibited prognostic value.

CONCLUSIONS

The 2cDi and Mi can be used, under certain methodologic conditions, as an objective indicator of prognostic value of the degree of aggressiveness of oral SCC.

Prediction value of radiosensitivity of hepatocarcinoma cells for apoptosis and micronucleus assay

AIM

To investigate the prediction value of radiosensitivity of hepatocarcinoma cells for apoptosis and micronucleus assay.

METHODS

Clonogenic assay, flow cytometry, and CB micronuclei assay were used to survey the cell survival rate, radiation-induced apoptosis and micronucleus frequency of hepatocarcinoma cell lines SMMC-7721, HL-7702, and HepG2 after being irradiated by X-ray at the dosage ranging 0-8 Gy.

RESULTS

After irradiation, there was a dose-effect relationship between micronucleus frequency and radiation dosage among the three cell lines (P<0.05). A positive relationship was observed between apoptosis and radiation dosage among the three cell lines. The HepG2 cells had a significant correlation (P<0.05) but apoptosis incidence had a negative relationship with micronucleus frequency. There was a positive relationship between apoptosis and radiation dosage and the correlation between SMMC-7721 and HL-7702 cell lines had a significant difference (P<0.01). After irradiation, a negative relationship between cell survival rate and radiation dosages was found among the three cell lines (P<0.01). There was a positive relationship between cell survival rate and micronucleus frequency (P<0.01). No correlation was observed between apoptosis and cell survival rate.

CONCLUSION

The radiosensitivity of hepatocarcinoma cells can be reflected by apoptosis and micronuclei. Detection of apoptosis and micronuclei could enhance the accuracy for predicting radiosensitivity.