Rabassa Martín E, Croce María V, Pereyra Adrián, Segal-Eiras Amada
Centre of Basic and Applied Immunological Research (CINIBA), Faculty of Medical Sciences, UNLP, Calle 60 y 120, 1900 La Plata, Argentina.
BMC Cancer. 2006 Oct 25;6:253. doi: 10.1186/1471-2407-6-253.
HNSCC progression to adjacent tissue and nodes may be mediated by altered glycoproteins and glycolipids such as MUC1 mucin. This report constitutes a detailed statistical study about MUC1 expression and anti-MUC1 immune responses in relation to different clinical and pathological parameters which may be useful to develop new anti HNSCC therapeutic strategies.
Fifty three pre treatment HNSCC patients were included: 26 (49.1%) bearing oral cavity tumors, 17 (32.1%) localized in the larynx and 10 (18.8%) in the pharynx. Three patients (5.7%) were at stage I, 5 (9.4%) stage II, 15 (28.3%) stage III and 30 (56.6%) at stage IV. MUC1 tumor expression was studied by immunohistochemistry employing two anti-MUC1 antibodies: CT33, anti cytoplasmic tail MUC1 polyclonal antibody (Ab) and C595 anti-peptidic core MUC1 monoclonal antibody. Serum levels of MUC1 and free anti-MUC1 antibodies were detected by ELISA and circulating immune complexes (CIC) by precipitation in polyethylene glycol (PEG) 3.5%; MUC1 isolation from circulating immune complexes was performed by protein A-sepharose CL-4B affinity chromatography followed by SDS-PAGE and Western blot. Statistical analysis consisted in Multivariate Principal Component Analysis (PCA); ANOVA test (Tukey's test) was employed to find differences among groups; nonparametrical correlations (Kendall's Tau) were applied when necessary. Statistical significance was set to p < 0.05 in all cases.
MUC1 cytoplasmic tail was detected in 40/50 (80%) and MUC1 protein core in 9/50 (18%) samples while serum MUC1 levels were elevated in 8/53 (15%) patients. A significant statistical correlation was found between MUC1 serum levels and anti-MUC1 IgG free antibodies, while a negative correlation between MUC1 serum levels and anti-MUC1 IgM free antibodies was found. Circulating immune complexes were elevated in 16/53 (30%) samples and were also statistically associated with advanced tumor stage. MUC1 was identified as an antigenic component of IgG circulating immune complexes. Moreover, poorly differentiated tumors were inversely correlated with tumor and serum MUC1 detection and positively correlated with node involvement and tumor mass.
Possibly, tumor cells produce MUC1 mucin which is liberated to the circulation and captured by IgG antibodies forming MUC1-IgG-CIC. Another interesting conclusion is that poorly differentiated tumors are inversely correlated with tumor and serum MUC1 detection.
头颈部鳞状细胞癌（HNSCC）向邻近组织和淋巴结的进展可能由糖蛋白和糖脂改变介导，如MUC1粘蛋白。本报告对MUC1表达及抗MUC1免疫反应与不同临床和病理参数的关系进行了详细的统计学研究，这可能有助于制定新的抗HNSCC治疗策略。
纳入53例HNSCC预处理患者：26例（49.1%）患有口腔肿瘤，17例（32.1%）位于喉部，10例（18.8%）位于咽部。3例（5.7%）处于I期，5例（9.4%）处于II期，15例（28.3%）处于III期，30例（56.6%）处于IV期。采用两种抗MUC1抗体通过免疫组织化学研究MUC1肿瘤表达：CT33，抗细胞质尾MUC1多克隆抗体（Ab）和C595抗肽核心MUC1单克隆抗体。通过酶联免疫吸附测定（ELISA）检测血清MUC1水平和游离抗MUC1抗体，通过在3.5%聚乙二醇（PEG）中沉淀检测循环免疫复合物（CIC）；通过蛋白A-琼脂糖CL-4B亲和色谱从循环免疫复合物中分离MUC1，随后进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和蛋白质印迹法。统计分析包括多变量主成分分析（PCA）；采用方差分析检验（Tukey检验）以发现组间差异；必要时应用非参数相关性（Kendall's Tau）。所有情况下设定统计学显著性为p < 0.05。
在40/50（80%）的样本中检测到MUC1细胞质尾，在9/50（18%）的样本中检测到MUC1蛋白核心，而8/53（15%）的患者血清MUC1水平升高。发现MUC1血清水平与抗MUC1 IgG游离抗体之间存在显著的统计学相关性，而MUC1血清水平与抗MUC1 IgM游离抗体之间存在负相关性。16/53（30%）的样本中循环免疫复合物升高，并且也与肿瘤晚期在统计学上相关。MUC1被鉴定为IgG循环免疫复合物的抗原成分。此外，低分化肿瘤与肿瘤和血清MUC1检测呈负相关，与淋巴结受累和肿瘤大小呈正相关。
肿瘤细胞可能产生MUC1粘蛋白，其释放到循环中并被IgG抗体捕获形成MUC1-IgG-CIC。另一个有趣的结论是低分化肿瘤与肿瘤和血清MUC1检测呈负相关。
