Telomeres of tumor
cells may be maintained by telomerase or by alternative
lengthening of telomeres (ALT). The standard ALT assay
requires Southern analysis of high molecular weight genomic
DNA. We aimed to establish and validate an ALT assay
suitable for archived paraffin-embedded tumors and to use it
to examine the prevalence and clinical significance of ALT in
various types of tumors that are often telomerase negative.