Abstract: Provided herein are methods for predicting the LKB1 status of a patient or a biological sample, comprising the measurement of particular gene expression levels relative to a set of reference levels that represent the gene expression level of a biological wild-type sample without LKB1 gene or protein loss or mutation and the gene expression level of a reference sample with LKB1 gene or protein loss or mutation. Further provided herein are methods for treating and/or preventing a cancer or a tumor syndrome in a patient, comprising administering an effective amount of a TOR kinase inhibitor to a patient having cancer or a tumor syndrome, characterized by particular gene expression levels.