ALELOS DO RS2023004 DO GENE PARK2 E A EXPRESSÃO DE PARKINA EM CÂNCER COLORRETAL

INTRODUCTION: In 2018, it was observed that advanced colorectal adenocarcinoma patients with increased parkin immunoexpression had improved survival rates. However, the reason for this protein expression variation remains unknown. AIMS: To determine the correlation between the PARK2 gene’s tag-SNP rs2023004 genotypes and parkin expression levels. MATERIALS AND METHODS: Analysis was conducted on 71 tumor and 62 surgical safety margin samples from patients with colorectal adenocarcinoma. Intestine samples from 12 patients undergoing surgery for non-cancer reasons were also used as controls. All samples were obtained from the Pathological Anatomy Service of HC-UFPR. DNA extraction from these samples, stored in paraffin, was carried out on two consecutive days. On the first day, tissue digestion and paraffin removal were performed. On the second day, purification was conducted. Quantification was performed using NanoDrop 2000™, and samples above 30 ng/µL were diluted to this concentration to ensure the highest possible quality of the PCR reaction. The samples were pipetted into a 96-well plate along with the rs2023004 probe, Master Mix, and Milli-Q water. Allelic discrimination was performed on the Quant Studio™. ANOVA and Student’s T-test were conducted to compare Parkin immunoexpression means in different tumor regions (superficial, intermediate, and deep) between different genotypes. RESULTS: Of the colorectal adenocarcinoma samples, 29.6% were homozygous TT, 14.1% were homozygous CC, and 46.5% were heterozygous CT. The remaining 9.9% of the samples did not amplify enough for the system to distinguish the emitted fluorescence. Among the surgical margin samples, 25.8% were TT, 16.1% were CC, and 40.3% were CT. The remaining 17.7% of the samples did not amplify. Regarding the control samples, 33.3% were TT, 25% were CC, and 33.3% were CT. Only 8.3% of the samples did not amplify. ANOVA and Student’s T-test were performed for each tumor layer and the surgical margins. In all cases, the p-values were greater than 0.05, indicating that the parkin immunoexpression means for each genotype are statistically equal. FINAL CONSIDERATIONS: While the rs2023004 variants did not significantly contribute to the explanation of the variability in parkin immunoexpression within colorectal adenocarcinoma under the specific conditions of this investigation, it cannot be dismissed.

KEYWORDS: Colorectal cancer; Parkin; PARK2; Single Nucleotide Polymorphism; SNP.