6451
The bcl - 2 gene can potentially encode 26 - and 22 - kDa proteins that differ only in their carboxyl tails because of an alternative splicing mechanism .
 bcl - 2 gene
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 bcl - 2 gene