People with several types of human papillomaviruses (HPVs) were up to more than 1.5 times more likely as their HPV-free counterparts to develop squamous cell carcinoma—particularly if they were taking immunosuppressive drugs.

In a study of 663 cases of squamous cell carcinoma (SCC), 898 cases of basal cell carcinoma (BCC), and 805 control cases in New Hampshire residents aged 25 to 74 years, people with SCC had a higher prevalence of beta type HPVs than did the controls. This relationship was not seen in people with BCC.

The individuals with SCC were 1.4 times more likely to have two or three types of beta HPVs, and 1.7 times more likely to have more than eight types. Long-term users of immunosuppressive agents (systemic glucocorticoids) appeared to have more than a threefold risk of SCC in relation to HPV, but the researchers acknowledged statistical limitations associated with this finding.

“An emerging body of evidence suggests a role of HPV in the occurrence of SCCs of the skin in the general population,” wrote the authors in an online report for BMJ. “Our findings…provide additional evidence for increasing risk with greater numbers of beta type infections rather than a model in which risk is associated with either a single HPV type or group of types.”

The team suggested that preventing or treating HPV infection may help reduce the economic and health burdens of SCC, an increasingly prevalent malignancy.