A topical fluorescent molecular contrast agent, PARPi-FL, can detect basal cell carcinoma through intact skin in as little as five minutes in ex vivo human tissues, according to new preclinical research published in the August issue of The Journal of Nuclear Medicine.

Data confirmed that PARPi-FL is non-toxic to the skin and does not cause systemic side effects, making it a potential one-stop-shop for diagnosis and management of basal cell carcinoma.

Basal cell carcinoma is the most common skin cancer, and early treatment typically leads to excellent outcomes.

Definitive diagnosis, however, depends on biopsy, an invasive procedure that can be painful and leave scars.

In addition, biopsies can delay diagnosis weeks to months and require patients to return for treatment after histopathologic confirmation.

Emerging nonsurgical therapies for early basal cell arcinomas could be delivered at the bedside, but they require noninvasive diagnostic tools with high accuracy, said Manu Jain, MD, research pathologist and optical imaging specialist, dermatology at Memorial Sloan Kettering Cancer Centre in New York.

Our study investigated the feasibility of using fluorescent confocal microscopy with PARPi-FL for enhancing basal cell carcinoma detection in the clinical setting.

The study evaluated the optimal dose, application time, and diagnostic performance of PARPi-FL using ex vivo human tissues, including specimens from plastic surgery, Mohs surgery (basal cell carcinomas), and fresh excisions (benign and basal cell carcinomas).

Researchers also investigated the feasibility of topical application using gauze and real-time in vivo imaging with a commercial FCM device in tumour-bearing mice.

Preclinical toxicology studies were conducted to determine safety as well.

A minimal topical dose of 10  M applied for two to five minutes via gauze achieved sufficient dermal penetration.

PARPi-FL generated a strong fluorescent signal in basal cell carcinoma lesions with significantly weaker signals in benign tissues, supporting its diagnostic capability.

Furthermore, preclinical data confirmed that PARPi-FL is safe for topical application, said Ashish Dhir, PhD, DABT, senior pharmacology and toxicology manager in the Office of Entrepreneurship and Commercialization at Memorial Sloan Kettering Cancer Centre in New York.

Incorporating this targeted dye into in vivo imaging could significantly improve diagnostic accuracy, reduce unnecessary biopsies of benign lesions, and enable timely, noninvasive treatment for basal cell carcinoma, noted Jain.

Importantly, since PARP1 is also overexpressed in melanoma, these results support the feasibility of extending this approach to melanoma, offering a promising tool for distinguishing malignant from benign pigmented lesions without biopsy.

Source: Society of Nuclear Medicine and Molecular Imaging