Tricolor fluorescence in situ hybridization analysis of a touch imprint from a resected lung tumor. Tumor cells contain fewer green signals (the surfactant protein A genomic probe) than red ones (chromosome 10 centromeric probe), but the same number of yellow signals (the PTEN genomic probe) as red ones, indicating surfactant protein A gene but not PTEN deletion in the lung tumor. For further details, see Jiang et al. on page 5417 in this issue.