This probe can be used to detect 1q21 and 1q23 aberrations, and is available in two tubes, each paired with a 1p13 heterozygous internal reference. In nephroblastoma, the 1p36 deletion probe is paired with the 1q21 internal reference, but 1p36 interpretation can be challenged if there are abnormal numbers of 1q (acquired or amplified, and missing). This probe is designed to detect two well-documented abnormal regions, 1q21 and 1q23, with 1p13 as an internal reference, and can be used to double-check the 1p36 probe after a 1q21 abnormality.