Mass spectrometry imaging in spatial biology of pancreatic cancer.

Pancreatic cancer remains one of the deadliest malignancies, due to its highly aggressive tumour biology and often late diagnosis at advanced stages. Profound intratumour heterogeneity and a complex tumour microenvironment (TME) are critical characteristics of pancreatic cancer that require untargeted and spatially resolved molecular analysis for their in-depth investigation. Mass spectrometry imaging (MSI) can fulfil these requirements and has provided valuable insights into the molecular mechanisms underlying pancreatic cancer and its precursor lesions. Here, we present key MSI-based studies in pancreatic cancer research, along with other spatial biology methodologies, covering applications ranging from biomarker discovery and tumour classification to the characterisation of treatment response and metastatic progression. In addition, current technical limitations, challenges in clinical translation and future directions driven by ongoing advancements in spatial omics are discussed. This review summarises the contributions of MSI and other spatial biology technologies in elucidating TME heterogeneity in pancreatic cancer and highlights their potential to substantially advance clinical diagnostics and therapeutic strategies.