SLIT2 and head and neck cancer: Frequent 4p allele loss has been reported in cancers that demonstrate SLIT2 methylation such as lung, breast and NB, and also in cancers in which SLIT2 methylation status has not been investigated including colorectal, bladder and head and neck cancers (Knowles et al, 1994; Rosin et al, 1995; Gryfe et al, 1997; Pershouse et al, 1997; Yustein et al, 1999; Girard et al, 2000).