BRAF and melanoma: For example, modeling loss of function in the microenvironment would require generating a floxed allele in an established mouse model of cancer (i.e. BRAF;PTEN mouse model of melanoma [Dankort et al., 2009; Dhomen et al., 2009] or the KRAS;TP53 model of pancreatic cancer [Hingorani et al., 2003], etc.)and then crossing with a Cre driven by a microenvironment-specific promoter.