# Imaging tumor associated macrophage (TAM) function

> **NIH NIH R01** · MASSACHUSETTS GENERAL HOSPITAL · 2020 · $380,871

## Abstract

Tumor-associated macrophages (TAM) have recently attracted much attention as they play key roles in tumor
spread and in response to therapy: TAM substantially accelerate the progression of untreated tumors; they
also markedly influence the efficacy of anticancer drugs, including checkpoint blockade immunotherapies.
Furthermore, targeting TAM themselves, e.g. through the colony-stimulating factor 1 receptor (CSF-1R), can
effectively control the progression of advanced tumors. However, TAM show considerable plasticity by
assuming opposing phenotypes and functions that can be either tumoricidal (e.g. M1-like cells) or tumorigenic
(e.g. M2-like cells) and currently there is a significant knowledge gap on how TAM function in vivo and how
these cells' activities can be harnessed to improve anticancer therapy. This is largely because most of our
knowledge on TAM has come from histological and in vitro profiling studies, which are are invaluable
methodological approaches but cannot address how TAM functions are integrated within the dynamic tumor
microenvironment (TME). The goal of this project is to perform high resolution imaging––in combination with
broader coverage imaging and complementary readouts––to reveal fundamental aspects of TAM and other
myeloid subtypes during tumor progression in vivo. Further, we aim to use imaging to uncover how most recent
treatments (e.g. anti-PD-(L)1 immune checkpoint blockers) and new promising approaches (CSF-1R inhibitors)
affect TAM functions in vivo and in turn how drug effects on TAM impact treatment efficacy. Specifically, to
advance our knowledge of TAM subtypes and other myeloid cells, we will combine: i) new mouse models and
reporters for these cells; ii) single cell resolution intravital imaging of tumor environments; iii) broad coverage
microscopic imaging and other ex vivo readouts; and iv) new computational analysis. Taken together, findings
from this research proposal should not only deepen our understanding of mechanisms regulating myeloid cell
responses but also help uncover new opportunities for next-generation immunotherapeutic strategies and TAM
imaging. This immunotherapy imaging project brings together tumor immunology (Pittet) and imaging
(Weissleder) expertise from two different laboratories. We are well positioned to achieve our goals, having
demonstrated the feasibility of the experiments outlined in this application.

## Key facts

- **NIH application ID:** 9875443
- **Project number:** 5R01CA206890-04
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Mikael PITTET
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $380,871
- **Award type:** 5
- **Project period:** 2017-03-21 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9875443

## Citation

> US National Institutes of Health, RePORTER application 9875443, Imaging tumor associated macrophage (TAM) function (5R01CA206890-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9875443. Licensed CC0.

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