488
Finally , in samples obtained from two patients with drug refractory ALL , BAC - derived probes applied to archived marrow cells demonstrated that a breakpoint occurred between MDR1 and sequences 500 - 1000 KB telomeric to MDR1 , consistent with a random chromosomal rearrangement .
 GENE: MDR1; GENE: MDR1
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 GENE: MDR1; GENE: MDR1