7986
Although neither constitutively activated MEK ( MEK - 2E ) nor v - Src was sufficient individually to differentiate the H19 - 7 cells , coexpression of constitutively activated MEK and v - Src induced neurite outgrowth .
 MEK, MEK - 2E, v - Src, MEK, v - Src
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 MEK, MEK - 2E, v - Src, MEK, v - Src