Anal SCC is related to HPV virus exposure with up to 95% of patients with Anal SCC having a concurrent high risk HPV infection.
HPV is a non-enveloped double stranded DNA virus and is the most frequent sexually transmitted infection. Most infections clear spontaneously, however, some can persist leading to dysplasias. There are over 30 different genotypes and not all are oncogenic. HPV produces oncogenic proteins that inhibit the function of p53 and retinoblastoma proteins.
It’s thought that immunosuppressive states such as HIV or the long term use of steroids (inflammatory bowel disease) can prevent HPV clearance and lead to a higher risk of dysplasias and squamous cell carcinomas.
Up to 90% of patients with Anal SCC have HPV 16, making it, by far the most common high risk HPV infection in this patient population. It is also possible to have coinfections with several oncogenic HPV virus genotypes; HPV16/18 being often observed. We don’t know whether a co-infection can affect progression to anal SCC or have an impact on relapse/recurrence of ASCC.
This is one of the questions we are hoping to answer with mASCARA.