Factors implicated in the assessment of aminolevulinic acid-induced protoporphyrin IX fluorescence

► Analysis of ALA-induced PpIX fluorescence in co-cultures of tumor and normal esophageal cell lines ► Comparable ALA-induced PpIX fluorescence intensities in tumor and normal cell lines ► Heterogeneous mitochondrial activity throughout the monolayers of tumor and normal esophageal cell lines ► Positive collagen immunostaining in all tumor and normal esophageal cell lines tested