The invention provides oligonucleotide or peptide nucleic acids, peptide nucleic acids, arrays, cells, methods and kits for determining the presence or absence of a SPARC promoter mutation indicative of a cancer's resistance or sensitivity to a therapeutic regimen. The method generally comprises determining presence or absence of a SPARC promoter mutation for a subject's cancer. The invention also provides for methods of identifying potential subjects having a resistant cancer for selection to administer an alternative therapy regimen. The invention also provides for methods of treating such subjects with a therapeutic regimen based on the subject's genotype.