A NOVEL STRATEGY FOR THE INVESTIGATION OF CLONALITY IN PRECANCEROUS DISEASE STATES AND EARLY STAGES OF TUMOR PROGRESSION

A novel strategy for clonality determination from only 100 cells using the polymerase chain reaction in amplifying a 511 bp region located w ithin the first intron of the human hypoxanthine phosphoribosyl transf erase (HPRT) gene has been devised. The strategy rests on several obse rvations: that this region in females contains two HpaII/MspI sites wh ose methylation remains both obligate with X chromosome inactivation a nd independent of tumor progression; and that this region contains sin gle base allelic polymorphisms in 5-10% of females which can be detect ed by denaturing gradient gel electrophoresis (DGGE) on the PCR produc t. In polymorphic individuals, multiple bands (homo- and heteroduplexe s) indicate multiclonality, single bands indicate monoclonality, and t heir comparative migrations indicate clonal identity/non-identity. (C) 1994 Academic Press, Inc.