Immunochemistry

 MDM2 overexpression

Cytogenetics

Two subtypes according to their karyotype:

 Type D cells exhibit a near-diploid karyotype, with very few or no chromosome changes.
 Type H cells exhibit a near-tetraploid karyotype and many structural changes.

 large marker chromosomes and/or ring chromosomes containing 12q-derived sequences in which MDM2 is consistently amplified
 centrosome amplification (#14695989#)

Molecular biology

 MDM2 amplification