Tung W S, Shevlin D W, Bartsch D, Norton J A, Wells S A, Goodfellow P J
Department of Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
Mol Carcinog. 1996 Jan;15(1):5-10. doi: 10.1002/(SICI)1098-2744(199601)15:1<5::AID-MC2>3.0.CO;2-K.
We examined the frequency of cyclin-dependent kinase (CDK) N2 alterations in differentiated and anaplastic thyroid cancers to assess the involvement of CDKN2 in the development of these cancers. The CDKN2 gene, which encodes the cell-cycle regulator p16, was recently shown to be mutated or deleted in many tumor cell lines. Its role in the genesis of primary tumors is uncertain, however. Tumor and corresponding normal DNAs were prepared by microdissection of paraffin-embedded tissue blocks or from frozen surgical specimens of 15 papillary, 15 follicular, and five anaplastic thyroid carcinomas. The entire CDKN2 coding region was screened by single-strand conformational variant analysis and direct sequencing of variants. The presence of homozygous deletions was evaluated by multiplex polymerase chain reaction (PCR) analysis. Loss of heterozygosity (LOH) in the CDKN2 region was assessed by using flanking polymorphic markers. Two somatic missense mutations were found among the 35 thyroid cancers, one in a follicular tumor and one in an anaplastic tumor. Multiplex PCR suggested the presence of homozygous deletion in one anaplastic tumor and hemizygous deletions in four tumors. LOH studies revealed loss of 9p sequences in four follicular (27%) and two anaplastic (50%) cancers. Our data suggest that alterations in CDKN2 played a role in a minority of thyroid cancers (three of 35). LOH in the region of CDKN2 is seen in a significant proportion of follicular and anaplastic but not papillary cancers. Loss of 9p sequences suggests a role for a tumor suppressor gene in the development of follicular and anaplastic thyroid cancers.
我们检测了分化型和间变性甲状腺癌中细胞周期蛋白依赖性激酶（CDK）N2改变的频率，以评估CDKN2在这些癌症发生中的作用。最近发现，编码细胞周期调节因子p16的CDKN2基因在许多肿瘤细胞系中发生突变或缺失。然而，其在原发性肿瘤发生中的作用尚不确定。通过对石蜡包埋组织块进行显微切割或从15例乳头状、15例滤泡状和5例间变性甲状腺癌的冷冻手术标本中制备肿瘤及相应的正常DNA。通过单链构象变异分析和变异体直接测序对整个CDKN2编码区进行筛查。通过多重聚合酶链反应（PCR）分析评估纯合缺失的存在。利用侧翼多态性标记评估CDKN2区域的杂合性缺失（LOH）。在35例甲状腺癌中发现了两个体细胞错义突变，一个在滤泡状肿瘤中，一个在间变性肿瘤中。多重PCR提示在1例间变性肿瘤中存在纯合缺失，在4例肿瘤中存在半合子缺失。LOH研究显示，在4例滤泡状癌（27%）和2例间变性癌（50%）中存在9p序列缺失。我们的数据表明，CDKN2改变在少数甲状腺癌（35例中的3例）中起作用。在相当比例的滤泡状癌和间变性癌而非乳头状癌中可见CDKN2区域的LOH。9p序列缺失提示一个肿瘤抑制基因在滤泡状癌和间变性甲状腺癌发生中起作用。
