The invention relates to a method for demonstration of the occurrence of a molecular event, particularly in a cell, characterised by the detection of the ‘solubilisation’ of a fixed protein marker (or the fixing of a solubilised protein marker) which is a direct or indirect marker for the occurrence of the particular molecular event. Said protein marker is present in the cell before the above detection, the cell being subjected to a permeabilisation of the plasma membrane before detection, which liberates the solubilised protein into the extracellular medium, the presence of the marker protein thus being detected in the cell or the extra-cellular medium by any appropriate means, which permits the detection of whether the solubilisation, or the fixing have taken place and, hence, the corresponding molecular event.