Spatial Transcriptomic Analysis of Pituitary Corticotroph Tumors

Context Spatial transcriptomic (ST) analysis of tumors provides a novel approach to studying gene expression along with the localization of tumor cells in their environment to uncover spatial interactions. Design We present ST analysis of corticotroph pituitary neuroendocrine tumors (PitNETs) from formalin-fixed, paraffin-embedded tissues. ST data were compared to immunohistochemistry results. Gene expression profiles were reviewed for cluster annotations, and differentially expressed genes were used for pathway analysis. Results Seven tumors were used for ST analysis. In situ annotation of tumor tissue was inferred from the gene expression profiles and was in concordance with the annotation made by a pathologist. Furthermore, relative gene expression in the tumor corresponded to common protein staining used in the evaluation of PitNETs, such as reticulin and Ki-67 index. Finally, we identified intratumor heterogeneity; clusters within the same tumor may present with different transcriptomic profiles, unveiling potential intratumor cell variability. Conclusion Together, our results provide the first attempt to clarify the spatial cell profile in PitNETs.