Schneider S S, Schick C, Fish K E, Miller E, Pena J C, Treter S D, Hui S M, Silverman G A
Department of Pediatrics, Harvard Medical School, Children's Hospital, Boston, MA 02115, USA.
Proc Natl Acad Sci U S A. 1995 Apr 11;92(8):3147-51. doi: 10.1073/pnas.92.8.3147.
The squamous cell carcinoma antigen (SCCA) is a member of the ovalbumin family of serine proteinase inhibitors (serpins). A neutral form of the protein is found in normal and some malignant squamous cells, whereas an acidic form is detected exclusively in tumor cells and in the circulation of patients with squamous cell tumors. In this report, we describe the cloning of the SCCA gene from normal genomic DNA. Surprisingly, two genes were found. They were tandemly arrayed and flanked by two other closely related serpins, plasminogen activator inhibitor type 2 (PAI2) and maspin at 18q21.3. The genomic structure of the two genes, SCCA1 and SCCA2, was highly conserved. The predicted amino acid sequences were 92% identical and suggested that the neutral form of the protein was encoded by SCCA1 and the acidic form was encoded by SCCA2. Further characterization of the region should determine whether the differential expression of the SCCA genes plays a causal role in development of more aggressive squamous cell carcinomas.
鳞状细胞癌抗原（SCCA）是丝氨酸蛋白酶抑制剂（丝氨酸蛋白酶抑制剂）卵清蛋白家族的成员。在正常和一些恶性鳞状细胞中发现该蛋白的中性形式，而酸性形式仅在肿瘤细胞和鳞状细胞肿瘤患者的循环中检测到。在本报告中，我们描述了从正常基因组DNA中克隆SCCA基因的过程。令人惊讶的是，发现了两个基因。它们串联排列，两侧是另外两个密切相关的丝氨酸蛋白酶抑制剂，即18q21.3处的纤溶酶原激活物抑制剂2型（PAI2）和乳腺丝抑蛋白。这两个基因SCCA1和SCCA2的基因组结构高度保守。预测的氨基酸序列有92%的同一性，表明该蛋白的中性形式由SCCA1编码，酸性形式由SCCA2编码。对该区域的进一步表征应确定SCCA基因的差异表达是否在更具侵袭性的鳞状细胞癌的发展中起因果作用。
