RB1-associated tumor predisposition syndrome

Tumors

 retinoblastoma
 post-radiation osteosarcoma

 secondary tumors arising in patients with retinoblastoma

• Almost two-thirds of the secondary tumors arising in patients with retinoblastoma are mesenchymal in origin.
• Over 60% of the mesenchymal tumors are osteosarcomas.
• The soft tissue sarcomas include:
  • fibrosarcoma,
  • leiomyosarcoma,
  • liposarcoma

 homozygous deletions of the RB1 locus in sporadic cases of:

• leiomyosarcoma,
• malignant fibrous histiocytoma,
• undifferentiated sarcoma in the absence of any history of retinoblastoma.