Utilizing FISH to determine the hemizygous or homozygous PTEN deletion status, Yoshimoto et al. (8) analyzed paired primary adenocarcinomas and regional lymph node metastasis derived from 10 patients and determined that only 1 of the 10 patients retained both copies of the PTEN locus in his matched pair biopsy. Here, PTEN is linked to adenocarcinoma.