Molecular pathologic analysis of Niban gene expression and mitochondrial alterations in thyroid cancer and oxyphilic cell tumors

Niban是一种新发现的肿瘤相关基因，首次在Eker大鼠多步肾癌模型中报道。虽然其功能尚不清楚，但据推测它属于应激蛋白家族。对Niban在人类肿瘤中的表达知之甚少。在本研究中，我们研究了Niban在包括甲状腺、嗜氧性和其他肿瘤在内的多种人体组织和肿瘤中的表达及其调控。在甲状腺肿瘤中，包括乳头状和嗜氧性肿瘤、头颈部鳞状细胞癌和头颈部鳞状细胞发育不良，经常检测到Niban的上调。免疫组化结果与RT-PCR结果和Western blot结果相关。在外显子和启动子中未检测到Niban突变。在研究的肿瘤中未检测到Niban启动子CpG岛的甲基化。Niban的表达与BRAF和GRIM突变无关，这两种突变在乳头状瘤和亲氧性肿瘤中经常被报道。综上所述，Niban的上调可能在某些肿瘤的致癌过程中起重要作用。虽然推测了Niban表达与线粒体功能改变的关系，但没有发现这种关系的直接证据。因为我们没有检测到Niban基因的任何突变或甲基化，所以Niban不太可能属于经典的致癌基因和/或肿瘤抑制基因群。

Niban is a newly identified cancer-related gene, which was first reported in multi-step renal carcinogenes is model of Eker rat. Although its function is unknown, it is assumed to belong to a stress protein family. Little is know about Niban expression in human tumors. In the present study, we investigated Niban expression and its regulations in various human tissues and tumors including thyroid, oxyphilic and other tumors. Up-regulation of Niban was frequently detected in thyroid tumors including papillary and oxyphilic tumors, head & neck squamous cell carcinomas and head & neck squamous dysplasias. Immunohistochemical results correlated with RT-PCR results and Western blot analysis. No mutations of Niban were detected in the exons and in the promoter. Methylation of Niban promoter CpG island was not detected in tumors studied. Niban expression was not correlated with BRAF and GRIM mutations, which were frequently reported in poapillary and oxyphilic tumors. In summary, up-regulation of Niban may play an important role in the carcinogenic process of some tumors. Although relationship of Niban expression and altered mitochondrial functions were speculated, no direct evidence for such relationship was found. Because we did not detect any mutations or methylations in Niban gene, it is unlikely that Niban belongs to classical groups of oncogenes and/or tumor suppressor genes.