Table 2.

Interpretation guidelines

Staining patternPositive therapy-guiding alterationLack of therapy-guiding alterationIndeterminate results
PTENCytoplasmicLoss of expression (absent)Retained expression (retained)
  • Nonneoplastic elements weaka

  • Incongruent staining pattern

  • Insufficient sample

RBNuclear
MLH1
MSH2
  • aStaining should be repeated in such a situation before indeterminate category is assigned.