背景:鳞状细胞癌(SCC)是最常见的口腔恶性肿瘤,一些驱动基因的体细胞突变与SCC的发展有关。透明细胞SCC(CCSCC)是SCC的一种罕见的组织学变体,在口腔CCSCC的鉴别诊断中必须考虑各种透明细胞肿瘤。根据口腔中报告的有限数量的CCSCC病例,CCSCC被认为是SCC的侵袭性变体,预后不良;然而,其遗传特征仍然未知。
方法:描述了一名89岁女性的上颌牙龈肿瘤,并使用免疫组织化学染色进行了研究,特殊染色,荧光原位杂交,和下一代测序(NGS)与一组定制的驱动基因,包括与SCC和透明细胞肿瘤发展相关的那些。
结果:组织病理学检查显示,异型上皮细胞增生,胞质丰富,胞核增大并位于中央。肿瘤是外生性的,穿透增殖。非典型透明细胞与常规SCC细胞连续。免疫组织化学分析显示,透明细胞对CKAE1/AE3和CK5/6呈阳性,对p63呈核阳性。相比之下,透明细胞为αSMA阴性,S100,HMB45,Melan-A,CD10和p16。p53免疫反应性表现出野生型表达模式。此外,透明细胞高碘酸希夫(PAS)阳性,淀粉酶-PAS阴性,粘液胺,阿尔西亚蓝。基于这些结果,CCSCC的诊断得到证实.透明细胞的分子分析鉴定出PIK3CAp.E542K(c.1624G>A)和HRASp.G12A(c.35G>C)体细胞突变被分类为致癌的。在TP53、EWSR1、AKT1、PTEN、BRAF,KRAS,NRAS,RASA1或MAML2。
结论:我们报告一例口腔CCSCC伴PIK3CA和HRAS突变。PIK3CA和/或HRAS突变的鉴定在SCC中很少见;然而,这两种突变都是抗肿瘤治疗的重要潜在靶点.对CCSCC基因突变的详细分析可能会导致对其生物学行为的更好理解和改善预后。以及与其他透明细胞肿瘤的鉴别诊断。
BACKGROUND: Squamous cell carcinoma (SCC) is the most common oral malignancy, and somatic mutations in some driver genes have been implicated in SCC development. Clear cell SCC (CCSCC) is a rare histological variant of SCC, and various clear cell neoplasms must be considered in the differential diagnosis of CCSCC in the oral cavity. Based on a limited number of CCSCC cases reported in the oral cavity, CCSCC is considered an aggressive variant of SCC with a poor prognosis; however, its genetic characteristics remain unknown.
METHODS: A maxillary gingival tumor in an 89-year-old female was described and investigated using immunohistochemical staining, special staining, fluorescence in situ hybridization, and next-generation sequencing (NGS) with a custom panel of driver genes, including those associated with SCC and clear cell neoplasm development.
RESULTS: Histopathological examination revealed a proliferation of atypical epithelial cells with abundant clear cytoplasm and enlarged and centrally placed round nuclei. The tumor was exophytic with deep, penetrating proliferation. The atypical clear cells were continuous with the conventional SCC cells. Immunohistochemical analysis showed that the clear cells were positive for CK AE1/AE3 and CK5/6 and nuclear-positive for p63. In contrast, the clear cells were negative for αSMA, S100, HMB45, Melan-A, CD10, and p16. p53 immunoreactivity exhibited a wild-type expression pattern. Additionally, the clear cells were positive for periodic acid-Schiff (PAS) and negative for diastase-PAS, mucicarmine, and Alcian blue. Based on these results, the diagnosis of CCSCC was confirmed. Molecular analysis of the clear cells identified PIK3CA p.E542K (c.1624G>A) and HRAS p.G12A (c.35 G>C) somatic mutations classified as oncogenic. No pathogenic variants were identified in TP53, EWSR1, AKT1, PTEN, BRAF, KRAS, NRAS, RASA1, or MAML2.
CONCLUSIONS: We report a case of CCSCC of the oral cavity with PIK3CA and HRAS mutations. The identification of PIK3CA and/or HRAS mutations is rare in SCC; however, both mutations are important potential targets for antitumor therapy. A detailed analysis of gene mutations in CCSCC may lead to a better understanding of its biological behavior and an improved prognosis, as well as a differential diagnosis from other clear cell neoplasms.