No statistical association between common fragile sites and nonrandom chromosome breakpoints in cancer cells.

Fragile sites and nonrandom chromosome breakpoints in cancer cells are not distributed at random within the genome, but occur mainly in the light G-bands. If this nonrandom distribution is taken into account and a statistical analysis for the association of these two phenomena within the same chromosome band is carried out, based on the 400-band karyotype, no significant association is found between the common fragile sites and cancer breakpoints although there remains an association between the rare fragile sites and cancer breakpoints. These results, along with other chromosome mapping evidence that rare fragile sites are not at the breakpoint in some cancer chromosome rearrangements, cast serious doubt on any role for fragile sites in oncogenesis.