2037
Therefore , in conjunction with a positive pregnancy test and the patient ' s clinical history , a severely depressed or absent serum PAPP - A level may aid in the diagnosis of extrauterine pregnancy .
 PAPP - A
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 PAPP - A