Early indications that cyclin C may function as a tumor suppressor came from loss of heterozygosity studies that found that the CCNC locus (6q21) is associated with loss or translocation in approximately 10% of cases of childhood acute lymphoblastic leukemia (T-ALL), with concomitant loss of one CCNC allele in over 90% of these cases [95]. Here, CCNC is linked to acute lymphoblastic leukemia.