Predictive markers for the sensitivity of breast cancer cells to PDT


Ziegler Verena Mag. rer. nat. B. rer. nat., doctoral student (


Predictive markers for the sensitivity of breast cancer cells to photodynamic therapy using ALA

Fluorescence diagnosis (FD) and photodynamic therapy (PDT) are methods for the detection or elimination of malignant lesions, both based on the special characteristics of a photosensitizing agent. This photosensitizer preferentially accumulates in malignant cells and has the potential to emit fluorescence (used in FD) or form radical oxygen species (used in PDT), when activated by visible light. Patients suffering from breast cancer could benefit from both aspects of photodynamic methods.

In individualized cancer treatment, knowledge about reliable predictive markers is of utmost importance to provide the best therapy, especially in heterogeneous diseases as breast cancer. Currently, little is known about predictive markers for FD or PDT efficiency, but recent studies showed an influence of cell proliferation and the state of differentiation on the susceptibility to PDT.

Therefore, this study is designed to compare the photodynamic susceptibility of breast cancer cell lines with different differentiation status and of diverse molecular subtypes to represent the spectrum of cellular variations seen in breast cancer. The expression of a range of cellular differentiation/proliferation markers, as well as enzymes involved ALA-PDT, will further be analyzed to find a correlation between the expression of these candidate markers and the sensitivity to photodynamic therapy.

The key issue addressed by this study is whether it is possible to predict the outcome of ALA-PDT and FD by the analysis of certain markers.