1287
Single - sperm typing techniques were performed for each sample by study of two informative short tandem repeats located either in or close to the retinoblastoma gene ( RB1 ) .
 retinoblastoma
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease 
Text: {0} 
Answer:
 retinoblastoma