Intratumoral genetic heterogeneity in non-small cell lung cancer: do single biopsies represent the complete tumor?
INTRODUCTION: Intratumoral genetic heterogeneity(ITH) describes a variable set of gene mutations within the same tumor. In this sense, it is known that tumors have different genetic patterns, but that they may even have differentiations within the same organism, causing cell subpopulations to perform different responses. Drug efficacy is variable and not yet conclusive, which increasingly leads to the need for further studies in the area. To this end, the following question about ITH stands out with regard to lung cancer, a neoplasm responsible for the highest number of deaths in male smokers: do the single biopsies represent the complete tumor? The objective, therefore, of the present study is to verify whether only a single biopsy is effective in the diagnosis and to analyze the interference of ITH in the treatment and prognosis of lung cancer.METHODOLOGY: descriptive studies on the use of biopsies were used to identify neoplasms from the following databases: European Journal of Cancer , The Lancet Oncology , Journal of Geriatric Oncology , PUBMED and SCIELO. The articles used were found from the following descriptors: Genetic heterogeneity. Lung neoplasms. Non-small cell lung cancer. Biopsy. Genetic markers. RESULTS: in nonsmall cell lung cancer (NSCLC), the presence of mutations promoting treatment resistance and a poor clinical prognosis were verified. Among them we can mention the expression, amplification and inversion / fusion of the EGFR, KRAS, BRAF, TP53, HER2, RH, MET and ALK genes. Biopsy is an investigative method of tissue collection with neoplastic suspicion for laboratory evaluation. However, it often does not analyze the ITH since one of the protocols most used today by oncologists has been to associate its use with the new generation genetic sequencing method, which broadens the view of the tumor's genetic variables. This fact confirms the limitations of the sampling of unique tumor regions and emphasizes the ability of multi-region sequencing to define the clonality of tumor events and to personalize therapeutic targets. DISCUSSION: The use of biopsy methods for investigative factors in neoplasms of laboratory evaluations is relevant to verify the CPNPC, in which mutations promoting resistance to treatment and poor clinical prognosis such as gene expression, amplification and inversion / fusion EGFR, KRAS, BRAF, TP53, HER2, RH, MET and ALK. However, laboratory biopsy methodology does not always analyze ITH. Thus, genetic sequencing proves to be the next generation procedure for analyzing tumor genetic variables; which demonstrates the lack of studies and mappings as authentic as possible in the specific clinical management for NSCLC. CONCLUSION: More studies are needed to deepen the mapping of tumor genetic variability in order to optimize and personalize the choice for the best treatment intrinsic to the identity of the tumor.
Keywords: Tumor genetic heterogeneity. Non-small cell lung cancer. Diverse mutations
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