In this study researchers propose to do a chart review of all patients that are treated outside of a clinical trial with imatinib, dasatinib, nilotinib, or any other tyrosine kinase inhibitor that becomes FDA approved for the managements of CML that come to MDACC for a second opinion. This is an important population of patients that differs in their management from patients treated in clinical trials for several reasons including but not limited to: 1. It represents a very large patient population receiving standard-dose therapy with TKI. We estimate that we have evaluated over 300 patients that fall in this category. 2. The follow-up for patients in the largest trial using standard-dose imatinib (the IRIS trial, with 553 patients in treated with imatinib) has been limited after the first 12 months. For example, the rate of molecular responses after the first 12 months of therapy was not obtained as samples stopped being collected at that time point. 3. Registration studies for dasatinib and nilotinib have similar limitations with limited follow-up and available information coming only from databases from the sponsors to which there is limited access to investigate dosing, chronic toxicities, second malignancies and other important aspects of therapy. 4. Patients who are or become pregnant during therapy with TKI have not been eligible for clinical trials with TKI or had to be taken off study. Thus, there is no information on the effect of TKI on imatinib on pregnancy and conception. We have followed several such patients at MDACC. 5. This is a patient population that follows therapy mostly as directed by their local oncologists. This is frequently less stringently adhered to the recommended guidelines for TKI therapy, with more frequent treatment interruptions, and frequently using suboptimal doses of imatinib (i.e., less than 300mg daily). The effect of these treatment interruptions and suboptimal dosing on response and development of resistance is unclear. Researchers plan to conduct a chart review of these patients to study their treatment course before their initial evaluation at MDACC, and between and during visits to MDACC.