ABCG2 and neoplasm: In the second phase, an example of a proposed protocol would be to exploit the genomic analysis of the biopsy and apply clinically tested and approved inhibitors (eg, febuxostat or elacridar for ABCG2) either alone or in combination, depending on how many of the predictive biomarkers come out positive prior to PDT in order to curb the main tumor resistance with respect to the treatment.