Although nonmutational mechanisms for low or undetectable ACYl enzymatic activity, protein, and mRNA expression are most frequently operant in SCLC, the demonstration of a mutation supports selection for ACYl inactivation.
Southern and northern analyses of ACY1 in SCLC cell lines failed to demonstrate any gross abnormalities of the ACY1 structural gene or instances of absent or aberrantly sized mRNA, respectively.
Since expression of ACY1, a housekeeping gene, is specifically reduced in many cases of SCLC, knowledge of its precise chromosomal position and identification of neighboring putative gene loci should facilitate investigation into the mechanism of this reduction.