the data indicate that approximately half of all retinoblastomas are homozygous for large portions of 13q , that the homozygosity occurs in vivo and not as an event secondary to culture of the tumor cells , that chromosome 13 homozygosity is not correlated with the degree of histopathologic differentiation of the tumor , and that the homozygosity occurs in both sporadic and hereditary retinoblastomas .
C1520537
13q
C0008655
chromosome 13