In vitro, growth inhibition varied significantly among individual ovarian cancer cell lines. IGF-II mRNA and phospho–IGF-IR protein expression were quantitatively correlated with response to ganitumab, and PTEN mutations conferred resistance to ganitumab....Moreover, assessment of tumor expression of IGF-II, phospho–IGF-IR, or PTEN status may help select patients with ovarian cancer who are most likely to benefit from ganitumab.