Table 4

Numbers, incidence, and types of primary CNS tumors in rats dying before experiment termination (unscheduled sacrifice, preterm rats)a

Site and histological classificationPreterm ratsb (n = 168)
SS (n = 17)SF (n = 19)ES (n = 34)EF (n = 35)EC (n = 39)SC (n = 24)
CNS
Total tumors011914c101
CNS tumor incidence (%)05.355.937.125.64.2
No. of CNS glial tumors011613104
Brain tumor incidence (%)0047.131.425.64.2
No. of brain tumors001612101
Glial
Oligodendroglioma001120
Astrocytoma0042c31
Mixed glioma008950
Ependymoma002000
Nonglial
Granular cell tumor001000
Spinal cord incidence (%)05.38.85.700
No. of spinal cord tumors013200
Glial
Astrocytoma011000
Mixed glioma002100
Nonglial
Undifferentiated000100
  • a All lesions in animals that died prior to the termination of the experiment are shown. The numbers of rats/group are shown in parentheses. Incidence in percentage; all other entries are numbers of tumors.

  • b See Table 3 <$REFLINK> for causes of death.

  • c Two tumors in one rat. All other rats had one tumor.