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Updated: May 21, 2026
Heterogeneity Mapping of Protein Expression in Tumors using Quantitative Immunofluorescence
Published on: October 25, 2011
Intra- and intertumor heterogeneities in total, chronic, and acute hypoxia in xenografted squamous cell carcinomas.
1Department of Radiotherapy and Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
Background:
Heterogeneously distributed hypoxia is a major characteristic of solid tumors. (Immuno-)fluorescence detection of hypoxia in experimental tumors is frequently assessed in a single central section; however, this may not necessarily be representative of the whole tumor. In order to determine whether analysis of one central section is exemplary of the whole tumor and whether different volumes have an impact on tumor oxygenation, we assessed the fractions of total (TH), chronic (CH), and acute hypoxia (AH) throughout different layers of tumors of varying volumes.
Materials And Methods:
Xenografted FaDu human squamous cell carcinomas of different volumes were investigated for intra- and intertumor heterogeneities. Tissue blocks located at the apical, central, and basal layer were sliced from individual tumors. Four serial cryosections were analyzed from each tissue block. Vital tumor tissue was explored for the distribution of Hoechst 33342 (perfusion), pimonidazole (hypoxia), and CD31 (endothelium) to assess TH, CH, and AH.
Results:
Fractions of TH, CH, and AH were consistently similar in the serial sections of individual tissue blocks. However, significant differences were found between the apical, central, and basal blocks that were even opposite depending on the tumor volume. Pooled data from all three tissue blocks revealed significantly higher fractions of hypoxia in the large tumors than in the small tumors.
Conclusion:
FaDu tumors exhibit a heterogeneous and volume-dependent oxygenation status. Assessing the average fractions of TH, CH, and AH from central blocks corresponds best to the average of the entire tumor. However, information on intratumor heterogeneities is lost, especially when considering tumors of substantially different volumes.
