Genetic testing of tumors is so important for individualizing treatments. Every cancer is molecularly different and knowing if your tumor exhibits any form of mutation could really help you in making your treatment decisions. For example, it is not uncommon for tumors to have a mutation in the p53 gene. Sometimes tumors have also been found to have a deletion in the ERCC1 gene, and research has recently shown that this gene might play a role in chemotherapy resistance, especially in ovarian cancers. So don't be afraid to talk to your doctor about genetic testing and how it might help in deciding which chemotherapy is right for you!