2035
These results suggest that UV -induced signal transduction is mediated via cell surface receptors that normally respond to biological stimulation , whereas H2O2 is able to partially bypass this requirement.
 cell surface receptors
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 cell surface receptors