SAR1A and papilloma: However, it is noteworthy that while loss of both SARA alleles, most of the benign papillomas were converted into malignant forms: 58.8%, 3.9%, and 5.9% of tumors in SARAΔ/Δ mice showed well-differentiated, moderately-differentiated, and poorly-differentiated SCCs, respectively (Figure 8B and C).