Dados do Resumo

Título

Analysis of MYC gene expression in gastric cancer in different perspectives

Introdução

Gastric carcinoma (GC) is an aggressive malignancy, making up 6% of cancers in Brazil. Family history and genetic syndromes are significant but not well understood risk factors. MYC, an oncogene often seen in cancer, plays a key role in cell proliferation, differentiation, and cycle progression. Thus, analyzing MYC expression patterns is crucial for understanding its role in GC carcinogenesis.

Objetivo

The aim of the study is to analyze, characterize, and discuss the gene expression patterns of MYC in different conditions.

Métodos

MYC gene expression patterns were analyzed using gastric transcriptome samples from João de Barros Barreto University Hospital (HUJBB). Parameters included field cancerization, Lauren histological type, neoadjuvant therapy, EBV or Helicobacter pylori presence, treatment response, and staging. Paired tumor, adjacent, and metaplastic tissue samples from 206 patients were analyzed (CEP: 47580121.9.0000.5634). Total RNA was extracted with TRIzol® and assessed using the 2200 TapeStation System. RNA-seq was performed on the NextSeq platform, with reads converted to FASTQ format and mapped with the Salmon tool in the hg38 GENCODE genome. Kruskal-Wallis and Benjamini-Hochberg tests were applied, and DESeq2 assessed differential gene expression, identifying genes with [Log2 (Fold-Change)] > 2 and adjusted p-value < 0.05 as differentially expressed (DEG). DEG were correlated with clinicopathological data to evaluate their predictive value in GC. All analyses were conducted using RStudio 4.4.1.

Resultados

Regarding cancerization fields, the Kruskal-Wallis test revealed significant differences in MYC expression (adjusted p-value<0.05). The Benjamini-Hochberg test showed differences between GC tumor and adjacent samples (adjusted p-value =0.0086), GC and metaplastic samples (adjusted p-value=0.000), and metaplastic and adjacent samples (adjusted p-value =0.004). MYC is overexpressed in gastric cancer tumors. For Lauren's histological types, the Benjamini-Hochberg test indicated a significant difference between diffuse and intestinal types (adjusted p-value=0.0031), with MYC overexpressed in the intestinal type. Other parameters, including neoadjuvant therapy, EBV, Helicobacter pylori, treatment response, and staging, did not show significant MYC expression (all adjusted p-value >0.05).

Conclusões

It was observed that MYC expression is altered between different fields of cancerization, such as between GC and adjacent tissue, GC and metaplastic tissue, and between metaplastic and adjacent tissue. Additionally, there was a significant difference in expression between Lauren's diffuse and intestinal types. This study observed hyperexpression in cases of gastric cancer of the Lauren's intestinal type. What is an important piece of information, considering the role of MYC in gastric cancer.

Palavras Chave

Transcriptome; Câncer; Expression