Adequacy criteria and reporting for prognostic and predictive profiling of biopsies from gastrointestinal neoplasia: A position paper from the Italian group of gastrointestinal pathologists, section of Italian society of anatomic pathology and cytology (GIPAD-SIAPeC-IAP)

: Precision oncology relies on precision diagnostics, and histopathological diagnosis, along with biomarker evaluation, currently represents the cornerstone for personalized treatment. In gastrointestinal neoplasms, diagnostic assessment and molecular profiling are often performed on biopsy tissue, which may be quantitatively/qualitatively limited. Therefore, appropriate sample management is essential to avoid unnecessary waste and to obtain all the information necessary for treatment planning. Several factors may significantly impact biomarker testing: (i) pre-analytical issues; (ii) heterogeneity in biomarker expression; (iii) lack of standardization in biomarker testing and evaluation. Moreover, in the metastatic setting, inadequate/incomplete clinical information can lead to inappropriate sample handling, with negative implications. The application of appropriate guidelines in testing and reporting biomarker status according to clinical context is, therefore, strongly encouraged. In this position paper, the Italian Group of Gastrointestinal Pathologists (GIPAD), a section of the Italian Society of Pathological Anatomy and Cytology (SIAPeC-IAP), aims to summarize all the clinical and pathological requirements for adequate assessment of prognostic and predictive biomarkers in the gastrointestinal oncology patient, from biopsy acquisition to diagnostic reporting.