Node and represents the number of shortest paths from node to

Among the 188 illicit drugs, only 86 (45.7 ) have unique human protein targets, which can be mapped to 73 unique human genes. We applied the GO Slim Classification tool implemented in the WebGestalt to examine the number distribution of the 73 illicit drugs' target genes among each GO Slim term as compared to that among the 1235 non-illicit drugs' target genes. We tested GO Slim terms in two GO 134404-52-7 chemical information domains: Biological Process and Molecular Function. For each GO Slim term, we performed a Fisher's exact test and then applied a cutoff p-value of 0.05 to identify GO Slim terms enriched in a set of target genes. We identified seven GO Slim terms that are significantly enriched in the illicit target genes (Table 1). Most of them are directly related to molecular transduction, transporter activity, and ion binding. It should be noted that most of the non-illicit drugs' target genes (902, 73.0 ) are involved in "metabolic process," which is much higher than the PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28966044 percentage of illicit drugs' target genes (33, 45.2 ) in that category. Additionally, some GO Slim terms such as "nucleotide binding," "hydrolase activity," and "transferase activity" comprise approximately 15-20 of the non-illicit drugs' target genes but jointly have only one illicit drugs' target gene. These results indicate that, compared to non-illicit drugs' targetgenes, the illicit drugs' target genes tend to be involved in the receptor process and signaling transduction. Pathway enrichment analyses were further conducted to identify over-represented canonical biological pathways among the illicit drugs' target genes compared to the other drugs' target PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/27766744 genes. Using WebGestalt, nineteen KEGG pathways were identified as being significantly enriched with the 73 illicit drugs' target genes and 163 significant pathways enriched with the non-illicit drugs' target genes (adjusted p-value