NK2 genes (NKX2 gene cluster in humans) encode for homeodomain-containing transcription factors that are conserved along the phylogeny. According to the most detailed classifications, vertebrate NKX2 genes are classified into two distinct families, NK2.1 and NK2.2. The former is constituted by NKX2-1 and NKX2-4 genes, which are homologous to the Drosophila scro gene; the latter includes NKX2-2 and NKX2-8 genes, which are homologous to the Drosophila vnd gene. Conservation of these genes is not only related to molecular structure and expression, but also to biological functions. In Drosophila and vertebrates, NK2 genes share roles in the development of ventral regions of the central nervous system. In vertebrates, NKX2 genes have a relevant role in the development of several other organs such as the thyroid, lung, and pancreas. Loss-of-function mutations in NKX2-1 and NKX2-2 are the monogenic cause of the brain-lung-thyroid syndrome and neonatal diabetes, respectively. Alterations in NKX2-4 and NKX2-8 genes may play a role in multifactorial diseases, autism spectrum disorder, and neural tube defects, respectively. NKX2-1, NKX2-2, and NKX2-8 are expressed in various cancer types as either oncogenes or tumor suppressor genes. Several data indicate that evaluation of their expression in tumors has diagnostic and/or prognostic value.

NK2 基因（人类的NKX2基因簇）编码包含同源结构域的转录因子，这些转录因子在系统发育中是保守的。根据最详细的分类，脊椎动物NKX2基因分为两个不同的家族：NK2.1和NK2.2。前者由NKX2-1和NKX2-4基因组成，与果蝇scro基因同源；后者包括NKX2-2和NKX2-8基因，它们与果蝇vnd基因同源。这些基因的保守性不仅与分子结构和表达有关，还与生物学功能有关。在果蝇和脊椎动物中，NK2 基因在中枢神经系统腹侧区域的发育中发挥着共同作用。在脊椎动物中，NKX2基因在甲状腺、肺和胰腺等其他几个器官的发育中发挥着相关作用。NKX2-1和NKX2-2的功能丧失突变分别是脑-肺-甲状腺综合征和新生儿糖尿病的单基因原因。NKX2-4和NKX2-8基因的改变可能分别在多因素疾病、自闭症谱系障碍和神经管缺陷中发挥作用。NKX2-1、NKX2-2和NKX2-8在各种癌症类型中作为癌基因或抑癌基因表达。一些数据表明，评估它们在肿瘤中的表达具有诊断和/或预后价值。