Basic research on the biology of meta-tetra(hydroxyphenyl) chlorin for photodynamic therapy in gynaecology: Somatic genotoxicity assayed withDrosophila melanogaster.

The well-established SMART test, a somatic mutation and recombination assay of Drosophila, was applied to assess the possible genotoxicity of sublethal meta-tetra(hydroxyphenyl) chlorin (mTHPC) photodynamic therapy (PDT) to clonogenic cells in situ. The SMART assay monitors the loss of heterozygosity (LOH) at selected cell-marker loci in clonogenic cells of the larval wing primordia. No evidence of genotoxicity was observed under conditions that killed between 38 and 86% of the exposed test larvae. Since the SMART assay is based on the oral uptake of the suspected genotoxic agent, the uptake kinetics of mTHPC by the assay's specific target cells must be known. Therefore, relevant studies are being carried out at present in order to draw final conclusions from this negative test result for genotoxicity.