the literature on AK comes from Australia, where the prevalence of AK is estimated at 40–50% in adults over 40, as compared to the United States and Europe, where prevalence is estimated at under 11–38% in adults. One study found that those who immigrated to Australia after age 20 had fewer AKs than native Australians in all age groups. Research Diagnostically, researchers are investigating the role of novel biomarkers to assist in determining which AKs are more likely to develop into cutaneous or metastatic SCC. Upregulation of matrix metalloproteinases (MMP) is seen in many different types of cancers, and the expression and production of MMP-7 in particular has been found to be elevated in SCC specifically. The role of serin peptidase inhibitors (Serpins) is also being investigated. SerpinA1 was found to be elevated in the keratinocytes of SCC cell lines, and SerpinA1 upregulation was correlated with SCC tumor progression in vivo. Further investigation into specific biomarkers could help providers better assess prognosis and determine best treatment approaches for particular lesions. In terms of treatment, a number of medications are being studied. Resiquimod is a TLR 7/8 agonist that works similarly to imiquimod, but is 10 to 100 times more potent; when used to treat AK lesions, complete response rates have range from 40 to 74%. Afamelanotide is a drug that induces the production of melanin by melanocytes to act as a protective factor against UVB radiation. It is being studied to determine its efficacy in preventing AKs in organ transplant patients who are on immunosuppressive therapy. Epidermal growth factor receptor (EGFR) inhibitors such as gefitinib, and anti-EGFR antibodies such as cetuximab are used in the treatment of various types of cancers, and are currently being investigated for potential use in the treatment and prevention of AKs. See also Age spot Freckle Lentigo Squamous cell carcinoma List of cutaneous conditions References External links Dermatology