THE INSTITUTE FOR CANCER RESEARCH 
7701 BUBHOLME AVENUE 
FOX CHASE • PHILADELPHIA, PENNSYLVANIA 10111 
(215) 342 - lOOO • CABLE ADDRESS- CANSKAHCH 
December 14, 1979 
Dr. Donald S. Fredrickson 
Director 
National Institutes of Health 
Bethesda, Maryland 20014 
Dear Dr. Fredrickson: 
I am writing this letter to let you know that I fully support your 
position that all recombinant DNA research performed with E_^ coli strain 
K12 should be classified P1/EK1. Although. I am not working with recombinant 
DNA myself, I feel that the potential risks of such research have been care- 
fully evaluated by well-informed specialists and that this classification is a 
a proper one. 
Yours very truly, 
Ra;f K. Gupta, Ph.D. 
RKG/jdi 
[ 494 ] 
THE FOX CHASE CANCER CENTER 
