The present invention provides 
diagnostic methods for predicting the effectiveness of treatment of an 
ovarian cancer patient with an IGF-1R 
kinase inhibitor. Methods are provided for predicting the sensitivity of tumor 
cell growth to inhibition by an IGF-1R 
kinase inhibitor, comprising assessing whether the 
tumor cells possess 
mutant K-RAS. The present invention thus provides a method of identifying patients with 
ovarian cancer who are most likely to benefit from treatment with an IGF-1R 
kinase inhibitor. Improved methods for treating 
cancer patients with IGF-1R kinase inhibitors that incorporate this methodology are also provided. The present invention also provides 
diagnostic methods for predicting the effectiveness of treatment of 
cancer patients with IGF-1R kinase inhibitors, based on a determination of the 
mutation status of the genes K-RAS, B-RAF, 
PTEN and PIK3CA, which can be used to identify tumor 
cell types that will be sensitive to IGF-1R kinase inhibitors, and also those that will be insensitive.