Laboratory of Human and Medical Genetics, Graduate Program of Genetics and Molecular Biology, Federal University of Pará, Belém, PA, 66075-110, Brazil.
Department of Clinical Dentistry - Health Sciences Center, Federal University of Ceará, Fortaleza, CE, 60020-181, Brazil.
BMC Cancer. 2018 Jul 6;18(1):721. doi: 10.1186/s12885-018-4631-z.
The theory of field effect suggests that the tumor-adjacent area, besides histopathologically normal, undergoes genetic and epigenetic changes that can eventually affect epithelial homeostasis, predisposing the patient to cancer development. One of the many molecular changes described in cancer are microRNAs (miRNAs), which regulates the expression of important genes during carcinogenesis. Thus, the aim of this study was to investigate the field effect in oral cancer.
We investigated the differential expression profile of four miRNAs (hsa-miR-221, hsa-miR-21, hsa-miR-135b, and hsa-miR-29c) in cancerous oral tissue, in tumor-adjacent tissue and and in non-cancerous tissue samples from healthy volunteers.
Our results showed significant overexpression profiles of all four studied miRNAs in cancerous oral tissue compared to non-cancerous samples, as well as in tumor-adjacent tissue compared to cancer-free tissue. No significant difference was found when comparing the expression profile of cancerous and tissue-adjacent tissue groups. We found a negative correlation between the expression of hsa-miR-21 expression and STAT3 in oral squamous cell carcinoma.
These results suggest that the tissue adjacent to cancer cannot be considered a normal tissue because its molecular aspects are significantly altered. Our data corroborates the hypothesis of field cancerization.
场效应理论表明，肿瘤相邻区域除了组织病理学上正常外，还会发生遗传和表观遗传变化，这些变化最终可能会影响上皮细胞的稳态，使患者易患癌症。在癌症中描述的众多分子变化之一是 microRNAs（miRNAs），它在癌变过程中调节重要基因的表达。因此，本研究旨在探讨口腔癌的场效应。
我们研究了四种 miRNAs（hsa-miR-221、hsa-miR-21、hsa-miR-135b 和 hsa-miR-29c）在癌性口腔组织、肿瘤相邻组织和健康志愿者的非癌性组织样本中的差异表达谱。
我们的结果显示，与非癌性样本相比，癌性口腔组织中所有四种研究的 miRNAs 均呈现出显著的过表达谱，而在肿瘤相邻组织中与无癌组织相比也是如此。在比较癌性和组织相邻组织组的表达谱时，没有发现显著差异。我们发现 hsa-miR-21 表达与口腔鳞状细胞癌中 STAT3 之间存在负相关。
这些结果表明，不能将癌症相邻的组织视为正常组织，因为其分子方面发生了显著改变。我们的数据证实了癌症化场的假说。
