Chemoprevention of oral cancer by topical application of black raspberries on high at-risk mucosa

Objective. To evaluate the preclinical efficacy of topical administration of freeze-dried black raspberries (BRBs) to inhibit the progression of premalignant oral lesions and modulate biomarkers of cancer development in high at-risk mucosa (HARM). Study Design. Hamster cheek pouches (HCPs) were treated with carcinogen for 6 weeks to initiate a HARM microenvironment. Subsequently, right HCPs were topically administered a BRB suspension in short-term or long-term studies. After 12 weeks, squamous cell carcinoma (SCC) multiplicity, SCC incidence, and cell proliferation rates were evaluated. mRNA expression was measured in short-term treated pouches for selected oral cancer biomarkers. Results. SCC multiplicity (- 41.3%), tumor incidence (- 37.1%), and proliferation rate (- 6.9%) were reduced in HCPs receiving BRBs. Topical BRBs correlated with an increase in RB1 expression in developing oral lesions. Conclusions. Topical BRBs inhibit SCC development when targeted to HARM tissues. These results support the translational role of BRBs to prevent oral cancer development in humans.