Human neuroblastomas are characterized by cytogenetic and molecular analysis as frequently containing deletions of distal 1p. Loss of heterozygosity (LOH) studies have localized a region of shared deletion to 1p35-36.1. Using the single-strand conformation polymorphism (SSCP) technique, we developed polymorphic assays for two genes, the amiloride-sensitive Na+/H+ antiporter (APNH) and tumor necrosis factor receptor 2 (TNFR2) genes, which map to this region. We used these SSCPs to detect LOH in a panel of neuroblastomas. Allelic loss was readily detected in 8 of 39 informative tumors. The SSCP-derived LOH results were consistent with LOH results generated from a set of distal 1p probes that identify restriction fragment length polymorphisms (RFLPs). The APNH locus could be excluded from the region of consistent deletion, but the TNFR2 locus could not be excluded. We conclude that the SSCP technique is a precise and efficient method for detecting LOH in human neoplasia.