Comparison of micronuclei frequency between smokers and non-smokers: a systematic review

ABSTRACT Introduction: Cancer results from the accumulation of several modifications in the genetic material and, therefore, it is possible to carry out its cytogenetic detection using biomarkers. Micronuclei (MN) have been addressed in the literature as biomarkers of genotoxic damage. These markers provide information on biological or biochemical changes in a target tissue at early stage, enabling a favorable prognosis. Objective: To compare whether the frequency of MN in active smokers is higher than that in non-smokers. Material and method: The search was performed in the Medical Literature Analysis and Retrieval System (PubMeb), in the Latin American and Caribbean Literature in Health Sciences (LILACS), and in the Scientific Electronic Electronic Library Online (SciELO), for articles published in the last ten years. Randomized clinical trials, with a cross-sectional design, which compared the MN frequency in the oral mucosa of adult smokers and non-smokers, were selected. Results: A total of 52 articles were identified, four of them were removed due to duplicity. From the remaining 48 studies, after reading their titles and abstracts, 14 remained, which had their full texts read. Finally, eight articles remained for the qualitative analysis. Discussion and conclusion: Individuals who use tobacco present genotoxic and cytotoxic damages that interfere in the mitosis process, which leads to MN formation. The hypothesis of smoking as the cause of this genetic alteration is corroborated by the authors when comparing the data obtained in their studies between risk groups and control groups.摘要 引言：癌症源于遗传物质的多种修饰累积，因此可借助生物标志物（biomarker）开展细胞遗传学检测。微核（Micronuclei，MN）作为遗传毒性损伤的生物标志物已在多篇文献中被研究探讨。此类标志物能够在早期阶段提供靶组织的生物学或生化变化信息，有助于实现良好的预后判断。 研究目的：对比主动吸烟者的微核频率是否高于非吸烟者。 材料与方法：本研究通过医学文献分析与检索系统（PubMed，原文标注为PubMeb）、拉丁美洲与加勒比卫生科学文献数据库（LILACS）以及科学电子在线图书馆（SciELO）进行文献检索，检索范围为近十年发表的相关文章。筛选标准为采用横断面设计的随机临床试验，且研究对比了成人吸烟者与非吸烟者口腔黏膜的微核频率。 结果：共检索到52篇文献，其中4篇因重复发表被剔除。剩余48篇文献经标题与摘要初筛后，纳入14篇文献进行全文阅读。最终共有8篇文献符合要求，用于本次定性分析。 讨论与结论：吸烟个体存在遗传毒性与细胞毒性损伤，此类损伤会干扰有丝分裂过程，进而导致微核形成。研究者通过对比风险组与对照组的研究数据，证实了“吸烟为此类遗传改变诱因”的假说。