Takahashi H, Iizuka H, Nakashima M, Wada T, Asano K, Ishida-Yamamoto A, Watanabe T
Department of Dermatology, Asahikawa Medical College, 2-1-1-1 Midorigaokahigashi,0788510, Asahikawa, Japan.
J Dermatol Sci. 2001 Jun;26(2):140-4. doi: 10.1016/s0923-1811(00)00170-5.
Receptor-binding cancer antigen expressed on SiSo cells (RCAS1), which is a type II membrane protein expressed on cervical carcinoma cells, induces apoptosis in RCAS1 receptor expressing cells. RCAS1 is thus presumed to protect tumor cells from immune surveillance by infiltrating RCAS1 receptor-positive immunocytes (Sonoda et al. Int J Oncol 1995; 6: 1899-1904; Nakashima et al. Nature Med 1999; 5: 938-942). We performed immunohistochemical analysis of RCAS1 expression in various skin tumors. RCAS1 was not detected in normal human epidermis. One of 21 seborrheic keratosis (4.8%), one of 12 actinic keratosis (8.3%), two of 16 keratoacanthomas (12.5%), and two of 14 basal cell carcinomas (14.2%) expressed RCAS1. RCAS1 was not detected in Bowen's disease (0/17). RCAS1 was positive in 45 of 61 (73.8%) squamous cell carcinomas. Interestingly, the expression of RCAS1 was mostly correlated with clinical stages of squamous cell carcinoma. It was found that 46.1% of stage I, 61.1% of stage II, 85.7% of stage III, and 83.3% of stage IV squamous cell carcinomas were RCAS1-positive. In addition, RCAS1 was found to be highly expressed in extramammary Paget's disease. Fifty nine of 63 extramammary Paget's disease samples (93.7%) were positive for RCAS1. Fifty eight (92%) showed co-expression of RCAS1 and carcinoembryonic antigen (CEA). While two of 24 cases of melanoma (8.3%) expressed RCAS1 antigen, none of 20 cases of nevus pigmentosus showed positive staining. These results indicate that RCAS1 is a highly sensitive marker for extramammary Paget's disease. RCAS1 is also expressed in various skin tumors including squamous cell carcinoma, where positive correlation with clinical staging was documented.
SiSo细胞上表达的受体结合癌抗原（RCAS1）是一种在宫颈癌细胞上表达的II型膜蛋白，可诱导表达RCAS1受体的细胞发生凋亡。因此，推测RCAS1通过浸润RCAS1受体阳性免疫细胞来保护肿瘤细胞免受免疫监视（Sonoda等人，《国际肿瘤学杂志》1995年；6：1899 - 1904；Nakashima等人，《自然医学》1999年；5：938 - 942）。我们对各种皮肤肿瘤中RCAS1的表达进行了免疫组织化学分析。在正常人表皮中未检测到RCAS1。21例脂溢性角化病中有1例（4.8%）、12例光化性角化病中有1例（8.3%）、16例角化棘皮瘤中有2例（12.5%）以及14例基底细胞癌中有2例（14.2%）表达RCAS1。在鲍温病中未检测到RCAS1（0/17）。61例鳞状细胞癌中有45例（73.8%）RCAS1呈阳性。有趣的是，RCAS1的表达大多与鳞状细胞癌的临床分期相关。发现I期鳞状细胞癌中有46.1%、II期中有61.1%、III期中有85.7%以及IV期中有83.3%的鳞状细胞癌RCAS1呈阳性。此外，发现RCAS1在乳腺外佩吉特病中高表达。63例乳腺外佩吉特病样本中有59例（93.7%）RCAS1呈阳性。58例（92%）显示RCAS1和癌胚抗原（CEA）共表达。24例黑色素瘤中有2例（8.3%）表达RCAS1抗原，20例色素痣均未显示阳性染色。这些结果表明RCAS1是乳腺外佩吉特病的高敏标志物。RCAS1也在包括鳞状细胞癌在内的各种皮肤肿瘤中表达，且与临床分期呈正相关。
