2354
With the discovery that TGFbeta1 was a potent growth inhibitor of epithelial cells , and the identification of inactivating mutations within the TGFbeta1 signaling pathway in cancers it became clear that TGFbeta1 signaling is a tumor suppressor pathway for early stages of cancer .
 epithelial cells, cancers, tumor, cancer
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 epithelial cells, cancers, tumor, cancer