Figure 1. Expression of NrCAM in a immune-resistant cancer cell line. This study was looking at the molecular mechanisms underlying tumor immune evasion. The immune-resistant cell line is produced by using multiple rounds of in vivo immune selection [1].

Figure 2. Expression of NrCAM in dermal lymphatic endothelial cells after treatment with tumor necrosis factor alpha.  This study analyzed inflammation-induced changes following treatment with TNF-alpha.  These experiments provided information about the mechanism involved in regulating the transmigration of leukocytes across the lymphatic vessel endothelium into the lymph nodes [2]. 

The microarray data presented above shows definite differential expression of NrCAM between the immune-resistant cancer cell line and an immune-susceptible cell line.  This is interesting due to the I-set and Ig domains present in NrCAM but it is difficult to make any conclusions about how these domains impact the immune evasion capabilities of cells.  The increased NrCAM expression in immune-resistant cells indicates that NrCAM may prevent the immune system from recognizing the tumor cells as foreign and allow the tumor to evade the immune response.   NrCAM expression is not as differential in the lymphatic endothelial cells treated with TNF-alpha or left untreated.  Compared with the immune-resistant cell data, this indicates that the expression of NrCAM might be induced or repressed in response to different environmental or cell-cycle dependent conditions.  

Though these data are not directly related to NrCAM's role in autism, they do provide evidence that NrCAM is differentially expressed in certain tissues treated with different conditions and maybe not in others.  NrCAM expression studies in neural tissues would be an important to look at its role in autism.  There has not been any experimental evidence to suggest that NrCAM is differentially expressed in nervous tissues of autistic individuals as compared to control nervous tissues. This would be an interesting study to conduct but it would require tissue samples which might be difficult to obtain. The studies could be conducted in rodent models where getting nervous tissue samples will not be as difficult. 

1. Lin KY, Lu D, Hung CF, Peng S. Ectopic expression of vascular cell adhesion molecule-1 as a new mechanism for tumor immune evasion. Cancer Res 2007 F1b 15;67(4):1832-41. 
2. Johnson LA, Clasper S, Holt AP, Lalor PF. An inflammation-induced mechanism for leukocyte transmigration across lymphatic vessel endothelium. J Exp Med 2006 Nov 27;203(12):2763-77.