Background

Liquid biopsy technologies are often unaffordable and unavailable in developing countries, despite these regions having the highest cancer burden and mortality rates. Current circulating tumor cell (CTC) technologies face significant clinical concerns, including non-specificity, low efficiency, high blood volume requirements, long turnaround times, and exorbitant costs (~$900–$1,400). We report an extremely low-cost, innovative nanosystem for the rapid enumeration of CTCs with higher specificity and efficiency.

Methods

We designed a nanosystem mediated by the conjugation of anti-EpCAM through a multi-reactive glutathione spacer, a carbon allotrope, and an amine-terminated dendrimer. The platform was evaluated for enhanced aqueous dispersibility and increased interaction with CTCs for rapid isolation and enumeration in 100 head and neck cancer (HNC) patients. These patients had various primary tumor sub-sites, including the oral cavity, larynx, hypopharynx, oropharynx, nasopharynx, salivary gland, and thyroid. The captured cells were immunostained, and the optimal fluorescence acquisition intensity was validated by accounting for CTCs with CK18 protein expression. Our method achieved the complete elimination of false-positive normal cell (NC) counts. The analysis was performed using only 1.5 ml of collected blood samples.

Results

The CTC distribution in the cohort study ranged from 1 to 85 cells per 1.5 ml of blood. In more than 80% of patients' CTCs, the quantitative estimation of anti-CK18 protein overexpression indicated an intensity approximately 10-fold higher than that of normal cells. Compared to treatment-naive, recurrent, and disease-free patients, the spread of CTC numbers across the clinical range appeared to be tight (close to the mean value). The CTC enumeration sensitivity linearity was ~99.2%, and the complete enumeration process time was under 3 hours per 1.5 ml of blood. Consequently, an efficient, rapid, and affordable CTC platform was designed and clinically validated.

Conclusions

The "OncoDiscover" liquid biopsy technology for CTC enumeration is poised to revolutionize the field due to its high sensitivity and affordability (~$120). It addresses a major unmet medical need in the developing world.