Spatial analyses of immune cell infiltration in cancer: current methods and future directions: A report of the International Immuno‐Oncology Biomarker Working Group on Breast Cancer
Authors: Page David B , Broeckx Glenn , Jahangir Chowdhury Arif , Verbandt Sara , Gupta Rajarsi R , Thagaard Jeppe , Khiroya Reena , Kos Zuzana , Abduljabbar Khalid , Acosta Haab Gabriela , Acs Balazs , Akturk Guray , Almeida Jonas S , Alvarado‐Cabrero Isabel , Azmoudeh‐Ardalan Farid , Badve Sunil , Baharun Nurkhairul Bariyah , Bellolio Enrique R , Bheemaraju Vydehi , Blenman Kim RM , Botinelly Mendonça Fujimoto Luciana , Bouchmaa Najat , Burgues Octavio , Cheang Maggie Chon U , Ciompi Francesco , Cooper Lee AD , Coosemans An , Corredor Germán , Dantas Portela Flavio Luis , Deman Frederik , Demaria Sandra , Dudgeon Sarah N , Elghazawy Mahmoud , Ely Scott , Fernandez‐Martín Claudio , Fineberg Susan , Fox Stephen B , Gallagher William M , Giltnane Jennifer M , Gnjatic Sacha , Gonzalez‐Ericsson Paula I , Grigoriadis Anita , Halama Niels , Hanna Matthew G , Harbhajanka Aparna , Hardas Alexandros , Hart Steven N , Hartman Johan , Hewitt Stephen , Hida Akira I , Horlings Hugo M , Husain Zaheed , Hytopoulos Evangelos , Irshad Sheeba , Janssen Emiel AM , Kahila Mohamed , Kataoka Tatsuki R , Kawaguchi Kosuke , Kharidehal Durga , Khramtsov Andrey I , Kiraz Umay , Kirtani Pawan , Kodach Liudmila L , Korski Konstanty , Kovács Anikó , Laenkholm Anne‐Vibeke , Lang‐Schwarz Corinna , Larsimont Denis , Lennerz Jochen K , Lerousseau Marvin , Li Xiaoxian , Ly Amy , Madabhushi Anant , Maley Sai K , Manur Narasimhamurthy Vidya , Marks Douglas K , McDonald Elizabeth S , Mehrotra Ravi , Michiels Stefan , Minhas Fayyaz ul Amir Afsar , Mittal Shachi , Moore David A , Mushtaq Shamim , Nighat Hussain , Papathomas Thomas , Penault‐Llorca Frederique , Perera Rashindrie D , Pinard Christopher J , Pinto‐Cardenas Juan Carlos , Pruneri Giancarlo , Pusztai Lajos , Rahman Arman , Rajpoot Nasir Mahmood , Rapoport Bernardo Leon , Rau Tilman T , Reis‐Filho Jorge S , Ribeiro Joana M , Rimm David , Vincent‐Salomon Anne , Salto‐Tellez Manuel , Saltz Joel , Sayed Shahin , Siziopikou Kalliopi P , Sotiriou Christos , Stenzinger Albrecht , Sughayer Maher A , Sur Daniel , Symmans Fraser , Tanaka Sunao , Taxter Timothy , Tejpar Sabine , Teuwen Jonas , Thompson E Aubrey , Tramm Trine , Tran William T , van der Laak Jeroen , van Diest Paul J , Verghese Gregory E , Viale Giuseppe , Vieth Michael , Wahab Noorul , Walter Thomas , Waumans Yannick , Wen Hannah Y , Yang Wentao , Yuan Yinyin , Adams Sylvia , Bartlett John Mark Seaverns , Loibl Sibylle , Denkert Carsten , Savas Peter , Loi Sherene , Salgado Roberto , Specht Stovgaard Elisabeth 
Published: August 2023

Modern histologic imaging platforms coupled with machine learning methods have provided new opportunities to map the spatial distribution of immune cells in the tumor microenvironment. However, there exists no standardized method for describing or analyzing spatial immune cell data, and most reported spatial analyses are rudimentary. In this review, we provide an overview of two approaches for reporting and analyzing spatial data (raster versus vector‐based). We then provide a compendium of spatial immune cell metrics that have been reported in the literature, summarizing prognostic associations in the context of a variety of cancers. We conclude by discussing two well‐described clinical biomarkers, the breast cancer stromal tumor infiltrating lymphocytes score and the colon cancer Immunoscore, and describe investigative opportunities to improve clinical utility of these spatial biomarkers. © 2023 The Pathological Society of Great Britain and Ireland.