RB

Epidemiology and Etiology:

· Autosomal dominant inheritance

· Germline RB1 gene defects

· Point mutations in the “RB pocket” – binding site for E2F (almost all)

· Deletions (15%)

· First tumour suppressor discovered

· RB protein is a key cell cycle regulator

· Must be inactivated (hyperphosphorylated) for the G1/S cell-cycle transition to occur

· Expressed in every cell type examined

·

Common sites:

· Eye

· Retinoblastoma

· retinocytoma

· Brain

· Pinealoma

· PNET

· Bone

· Osteosarcoma

· Soft tissue

· Sarcomas

· Skin:

· melanoma

Gross features:

·

Histologic features:

·

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

· RB1 sequencing

· Deletion testing:

· MLPA

· FISH

· Heterozygosity testing

· Quantitative multiplex PCR

Other features:

·

References:

· Kumar V, Fausto N, Abbas A. Robbins & Cotran Pathologic Basis of Disease, Seventh Edition. 7th ed. Saunders; 2004.

· Genetests.org (2009)