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Ciompi, Francesco

https://orcid.org/0000-0001-8327-9606

Mayo Clinic

Radboud University Medical Center

Citations 5

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

The Journal of Pathology | January 17, 2024 | Volume: 262 | Issue: 3 | Pages: 271-288

10.1002/path.6238 Get It

Abstract Recent advances in the field of immuno‐oncology have brought transformative changes in the management of cancer patients. The immune profile of tumours has been found to have key value in predicting disease prognosis and treatment response in various cancers. Multiplex immunohistochemistry and immunofluorescence have emerged as potent tools for the simultaneous detection of multiple protein biomarkers in a single tissue section, thereby expanding opportunities for molecular and immune profiling while preserving tissue samples. By establishing the phenotype of individual tumour cells when distributed within a mixed cell population, the identification of clinically relevant biomarkers with high‐throughput multiplex immunophenotyping of tumour samples has great potential to guide appropriate treatment choices. Moreover, the emergence of novel multi‐marker imaging approaches can now provide unprecedented insights into the tumour microenvironment, including the potential interplay between various cell types. However, there are significant challenges to widespread integration of these technologies in daily research and clinical practice. This review addresses the challenges and potential solutions within a structured framework of action from a regulatory and clinical trial perspective. New developments within the field of immunophenotyping using multiplexed tissue imaging platforms and associated digital pathology are also described, with a specific focus on translational implications across different subtypes of cancer. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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
Page, David B. , Broeckx, Glenn , Jahangir, Chowdhury Arif , Verbandt, Sara , Gupta, Rajarsi , Thagaard, Jeppe , Khiroya, Reena, Kos, Zuzana , Haab, Gabriela Acosta , Ács, Balázs , Alvarado‐Cabrero, Isabel , Baharun, Nurkhairul Bariyah, Bellolio, Enrique , Bheemaraju, Vydehi, Blenman, Kim RM, Fujimoto, Luciana Botinelly Mendonça , Bouchmaa, Najat , Burgues, Octavio, Cheang, Maggie C.U. , Ciompi, Francesco , Cooper, Lee , Coosemans, An , Corredor, Germán, Portela, Flávio Luis Dantas , Deman, Frederik , Dudgeon, Sarah , Elghazawy, Mahmoud , Ely, Scott , Fernandez‐Martín, Claudio , Fineberg, Susan , Gnjatic, Sacha , Halama, Niels , Hanna, Matthew G, Harbhajanka, Aparna , Hardas, Alexandros , Hartman, Johan , Hewitt, Stephen M. , Hida, Akira I. , Husain, Zaheed, Hytopoulos, Evangelos, Irshad, Sheeba , Janssen, Emiel A. M., Kahila, Mohamed, Kataoka, Tatsuki R. , Kawaguchi, Kosuke, Durga, Kharidehal, Khramtsov, Andrey , Kirtani, Pawan, Korski, Konstanty, Lænkholm, Anne‐Vibeke , Lang‐Schwarz, Corinna , Larsimont, Denis , Lennerz, Jochen K. , Li, Xiaoxian , Maley, Sai, Narasimhamurthy, Vidya Manur, Marks, Douglas K. , Mehrotra, Ravi , Michiels, Stefan, Mittal, Shachi , Mushtaq, Shamim , Hussain, Nighat , Papathomas, Thomas , Perera, Rashindrie , Pinard, Christopher J. , Pinto‐Cardenas, Juan Carlos , Rau, Tilman T. , Ribeiro, Joana , Salto‐Tellez, Manuel , Siziopikou, Kalliopi P. , Sotiriou, Christos, Stenzinger, Albrecht , Sughayer, Maher A. , Symmans, Fraser, Tanaka, Sunao , Taxter, Timothy , Tejpar, Sabine , Teuwen, Jonas, Thompson, E. Aubrey , Tramm, Trine , Tran, William T, Laak, Jeroen van der , Verghese, Gregory , Viale, Giuseppe , Vieth, Michael, Wahab, Noorul , Walter, Thomas , Waumans, Yannick , Wen, Hannah Y. , Yang, Wentao , Yuan, Yinyin, Bartlett, John Mark Seaverns, Loibl, Sibylle , Loi, Sherene , Salgado, Roberto , Stovgaard, Elisabeth Specht , Symmans, W. Fraser , Kahila, Mohamed M. , Gupta, Rajarsi R , Dantas Portela, Flavio Luis , Elghazawy, Mahmoud , Gonzalez-Ericsson, Paula I , Grigoriadis, Anita , Chardas, Alexandros , Hart, Steven N , Hartman, Johan , Kataoka, Tatsuki R , Rau, Tilman T , Reis-Filho, Jorge S , Rimm, David , Verghese, Gregory E , Wahab, Noorul , Gnjatic, Sacha , Broeckx, Glenn , Cheang, Maggie Chon U , Symmans, W Fraser , Lennerz, Jochen , Loi, Sherene , Acs, Balazs , Walter, Thomas , Irshad, Sheeba , McDonald, Elizabeth S. , AbdulJabbar, Khalid , Aktürk, Güray , Almeida, Jonas S. , Ardalan, Farid Azmoudeh , Badve, Sunil, Corredor, Germán , Demaria, Sandra , Fox, Stephen B. , Gallagher, William M. , Giltnane, Jennifer Margaret , González-Ericsson, Paula I. , Hart, Steven N. , Horlings, Hugo , Kawaguchi, Kosuke , Kiraz, Umay , Kodach, Liudmila L. , Kovács, Anikó , Lerousseau, Marvin , Ly, Amy , Madabhushi, Anant , Michiels, Stefan , Minhas, Fayyaz , Moore, David , Penault-Llorca, Frederique Madeleine , Pruneri, Giancarlo , Pusztai, Lajos , Rahman, Arman , Rajpoot, Nasir , Rapoport, Bernardo L. , Reis‐Filho, Jorge S. , Rimm, David L. , Vincent‐Salomon, Anne , Saltz, Joel , Sayed, Shahin , Sur, Daniel Genel , Tran, William T, Diest, P. J. van , Yuan, Yinyin , Adams, Sylvia , Bartlett, John M.S. , Denkert, Carsten , Savas, Peter Stephen

The Journal of Pathology | August 23, 2023 | Volume: 260 | Issue: 5 | Pages: 514-532

10.1002/path.6165 Get It

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

The Journal of Pathology | August 23, 2023 | Volume: 260 | Issue: 5 | Pages: 498-513

10.1002/path.6155 Get It

AbstractThe clinical significance of the tumor‐immune interaction in breast cancer is now established, and tumor‐infiltrating lymphocytes (TILs) have emerged as predictive and prognostic biomarkers for patients with triple‐negative (estrogen receptor, progesterone receptor, and HER2‐negative) breast cancer and HER2‐positive breast cancer. How computational assessments of TILs might complement manual TIL assessment in trial and daily practices is currently debated. Recent efforts to use machine learning (ML) to automatically evaluate TILs have shown promising results. We review state‐of‐the‐art approaches and identify pitfalls and challenges of automated TIL evaluation by studying the root cause of ML discordances in comparison to manual TIL quantification. We categorize our findings into four main topics: (1) technical slide issues, (2) ML and image analysis aspects, (3) data challenges, and (4) validation issues. The main reason for discordant assessments is the inclusion of false‐positive areas or cells identified by performance on certain tissue patterns or design choices in the computational implementation. To aid the adoption of ML for TIL assessment, we provide an in‐depth discussion of ML and image analysis, including validation issues that need to be considered before reliable computational reporting of TILs can be incorporated into the trial and routine clinical management of patients with triple‐negative breast cancer. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
Abstract P2-11-34: Mitotic spindle hotspot counting using deep learning networks is highly associated with clinical outcomes in patients with early-stage triple-negative breast cancer who did not receive systemic therapy
Leon‐Ferre, Roberto A. , Zahrieh, David M. , Salgado, Roberto, Balkenkohl, Maschenka, Carter, Jodi M. , Sinnwell, Jason P. , Salgado, Roberto , Suman, Vera J. , Hillman, David W. , Boughey, Judy C. , Kalari, Krishna R. , Couch, Fergus J. , Ingle, James N. , Ciompi, Francesco , Laak, Jeroen van der , Goetz, Matthew P.

Cancer Research | March 2, 2023 | Volume: 83 | Issue: 5_Supplement | Pages: P2-11-34-P2-11-34

10.1158/1538-7445.sabcs22-p2-11-34 Get It

Abstract Background: Triple-negative breast cancers (TNBC) exhibit high rates of recurrence and mortality. However, recent studies suggest that a subset of patients (pts) with early-stage TNBC enriched in tumor-infiltrating lymphocytes (TILs) have excellent clinical outcomes even in the absence of systemic therapy. Additional histological biomarkers that could identify pts for future systemic therapy escalation/de-escalation strategies are of great interest. TNBC are frequently highly proliferative with abundant mitoses. However, classic markers of proliferation (manual mitosis counting and Ki-67) appear to offer no prognostic value. Here, we evaluated the prognostic effects of automated mitotic spindle hotspot (AMSH) counting on RFS in independent cohorts of systemically untreated early-stage TNBC. Methods: AMSH counting was conducted with a state-of-the-art deep learning algorithm trained on the detection of mitoses within 2 mm2 areas with the highest mitotic density (i.e. hotspots) in digital H&E images. Details of the development, training and validation of the algorithm were published previously [1] in a cohort of unselected TNBC. We obtained AMSH counts in a centrally confirmed TNBC cohort from Mayo Clinic [2] and focused our analysis on pts who received locoregional therapy but no systemic therapy. Using a fractional polynomial analysis with a multivariable proportional hazards regression model, we confirmed the assumption of linearity in the log hazard for the continuous variable AMSH and evaluated whether AMSH counts were prognostic of RFS. We corroborated our findings in an independent cohort of systemically untreated TNBC pts from the Radboud University Medical Center in the Netherlands (Radboud Cohort). Results are reported at a median follow-up of 8.1 and 6.7 years for the Mayo and Netherlands cohorts, respectively. Results: Among 182 pts with who did not receive systemic therapy in the Mayo Cohort, 140 (77%) with available AMSH counts were included. The mean age was 61 (range: 31-94), 71% were postmenopausal, 67% had tumors ≤ 2cm, and 83% were node-negative. As expected, most tumors were Nottingham grade 3 (84%) and had a high Ki-67 proliferation index (54% with Ki-67 >30%). Most tumors (73%) had stromal TILs ≤ 30%. The median AMSH count was 18 (IQR: 8, 42). AMSH counts were linearly associated with grade and tumor size, with the proportion of pts with grade 3 tumors and size > 2 cm increasing as the AMSH counts increased (p=0.007 and p=0.059, respectively). In a multivariate model controlling for nodal status, tumor size, and stromal TILs, AMSH counts were independently associated with RFS (p< 0.0001). For every 10-point increase in the AMSH count, we observed a 17% increase in the risk of experiencing an RFS event (HR 1.17, 95% CI 1.08-1.26). We corroborated our findings in the Radboud Cohort (n=126). The mean age was 68 (range: 40-96), and 81% were node-negative. While the median AMSH count was 36 (IQR: 16-63), higher than in the Mayo Cohort (p=0.004), the prognostic impact was similar, with a significant association between AMSH count and RFS (p=0.028) in a multivariate model corrected for nodal status, tumor size, and stromal TILs. For every 10-point increase in the AMSH count in the Netherlands cohort, we observed a 9% increase in the risk of experiencing an RFS event (HR 1.09, 95% CI 1.01-1.17). RFS rates according to AMSH counts for both cohorts are shown in the Table. Conclusions: AMSH counting is a new proliferation biomarker that provides prognostic value independent of nodal status, tumor size, and stromal TILs in systemically untreated early-stage TNBC. Plans are underway to evaluate AMSH counts in additional cohorts of systemically untreated TNBC, and in other disease settings such as prior to neoadjuvant systemic therapy. If validated, this biomarker should be prospectively evaluated as a potential selection biomarker in clinical trials of systemic therapy de-escalation. References: 1. PMID: 29994086 2. PMID: 28913760 Table RFS according to AMSH counts in the Mayo and Radboud Cohorts Citation Format: Roberto A. Leon-Ferre, Jodi M. Carter, David Zahrieh, Jason P. Sinnwell, Roberto Salgado, Vera Suman, David Hillman, Judy C. Boughey, Krishna R. Kalari, Fergus J. Couch, James N. Ingle, Maschenka Balkenkohl, Francesco Ciompi, Jeroen van der Laak, Matthew P. Goetz. Mitotic spindle hotspot counting using deep learning networks is highly associated with clinical outcomes in patients with early-stage triple-negative breast cancer who did not receive systemic therapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-11-34.
Prognostic value of deep learning based mitotic count in hormonal receptor- and HER2-positive breast cancer
Mercan, Caner , Tessier, Leslie, Tellez, David , Salgado, Roberto , Joensuu, Heikki , Loi, Sherene , Michiels, Stefan , Larsimont, Denis , Wegscheider, Anne-Sophie , Niendorf, Axel, Laak, Jeroen van der , Joensuu, Heikki , Loi, Sherene , Balkenhol, Maschenka C. A. , Sherman, Mark E. , Bult, Peter , Ciompi, Francesco

No container title available | February 3, 2023 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.21203/rs.3.rs-2408990/v1 Get It

Abstract The discovery of molecular subtypes has corroborated the heterogeneity of breast cancers. But in clinical routine, treatment selection relies on measuring the aggressiveness of the tumor via histopathology, which is routinely based on grading, a prognostic yet laborious, poorly reproducible, and subjective procedure defined more than 30 years ago, before molecular subtypes existed. In this paper, we present an interpretable deep learning-based computer-aided diagnosis method to automate mitotic count, one of the components of grading; the method complies with current guidelines and automates hot-spot finding on full digital whole-slide images of routinely prepared pathologic slides stained with hematoxylin and eosin. We use the computer model to query the current “one-size-fits-all” mitotic count procedure by investigating subtype-specific prognostic value of mitotic count using an external independent large-scale multicentric dataset of 1,709 breast cancers. We show that for human epidermal growth factor-2 (HER2) positive tumors, mitotic count was not prognostic. In hormone-receptor positive/HER2 negative cancers, an average mitotic count density different from clinically used cut offs predicted worse recurrence free survival in multivariable analysis, adjusted for known clinical prognosticators. We provided some first experimental evidence that the prognostic role of mitotic count should be reviewed.