A method of deriving a value for % biomarker positivity for all cells or, optionally, one or more subsets thereof present in a field of view, comprising: (i) generating an image of first fluorescence signals representative of nuclei of all cells present in a field of view, and dilating the first fluorescence signals to a diameter of that of an entire cell to construct a first mask of all cells present in the field of view; (ii) constructing a second mask of second fluorescence signals representative of all areas present in the field of view, which express a subset biomarker; (iii) optionally, constructing a third mask of third fluorescence signals representative of all areas present in the field of view, which express a first biomarker of interest; (iv) combining said first and second masks in a manner that provides a fourth mask comprising fluorescence signals representative of all cells in the field of view, which also express the subset biomarker; (v) optionally, combining said first and third masks in a manner that provides a fifth mask comprising fluorescence signals representative of all cells in the field of view, which also express the first biomarker of interest; (vi) deriving a value for PBP for all cells expressing the subset biomarker by dividing the total area of the fourth mask by the total area of the first mask; (vii) optionally, combining said fourth and fifth masks in a manner that provides a sixth mask comprising fluorescence signals representative of all cells in the field of view, which (a) express the subset biomarker and the first biomarker of interest; or (b) express the subset biomarker in the absence of the first biomarker of interest; and (viii) optionally, deriving a value for PBP for the first subset of all cells which either (a) express the subset biomarker and the first biomarker of interest or (b) express the subset biomarker in the absence of the first biomarker of interest, by dividing the total area of the sixth mask by the total area of the fourth mask. (i) generating an image of first fluorescence signals representative of nuclei of all cells present in a field of view, and dilating the first fluorescence signals to a diameter of that of an entire cell to construct a first mask of all cells present in the field of view; (ii) constructing a second mask of second fluorescence signals representative of all areas present in the field of view, which express a subset biomarker; (iii) optionally, constructing a third mask of third fluorescence signals representative of all areas present in the field of view, which express a first biomarker of interest; (iv) combining said first and second masks in a manner that provides a fourth mask comprising fluorescence signals representative of all cells in the field of view, which also express the subset biomarker; (v) optionally, combining said first and third masks in a manner that provides a fifth mask comprising fluorescence signals representative of all cells in the field of view, which also express the first biomarker of interest; (vi) deriving a value for PBP for all cells expressing the subset biomarker by dividing the total area of the fourth mask by the total area of the first mask; (vii) optionally, combining said fourth and fifth masks in a manner that provides a sixth mask comprising fluorescence signals representative of all cells in the field of view, which (a) express the subset biomarker and the first biomarker of interest; or (b) express the subset biomarker in the absence of the first biomarker of interest; and (a) express the subset biomarker and the first biomarker of interest; or (b) express the subset biomarker in the absence of the first biomarker of interest; and (viii) optionally, deriving a value for PBP for the first subset of all cells which either (a) express the subset biomarker and the first biomarker of interest or (b) express the subset biomarker in the absence of the first biomarker of interest, by dividing the total area of the sixth mask by the total area of the fourth mask.