# In Vivo Oncogene-Induced Tumorigenesis and Escape

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2024 · $424,531

## Abstract

Recurrent breast cancer is typically an incurable disease. Consequently, the tendency of breast cancers
to recur following treatment is the most important determinant of clinical outcome. Recurrent tumors arise from
the reservoir of residual tumor cells (RTCs) that can persist in patients in a presumed dormant state for
decades after treatment of their primary tumor. As such, minimal residual disease, tumor dormancy, and
recurrence constitute fundamental manifestations of tumor progression that collectively are responsible for the
vast majority of breast cancer deaths. Despite their unrivaled clinical importance, however, the mechanisms
underlying them are largely unknown. Consequently, understanding the biology of RTCs and elucidating the
molecular pathways that contribute to tumor dormancy and recurrence is a critical priority in cancer research.
 We propose that disabling the survival mechanisms by which dormant RTCs persist in breast cancer
patients following treatment will deplete this critical reservoir of cells, reduce tumor recurrence, and thereby
improve patient survival. Using genetically engineered mouse (GEM) models that faithfully recapitulate tumor
dormancy and recurrence, we have identified a Sox5-associated osteochondrogenesis-like program that is
markedly upregulated in dormant RTCs, subsequently downregulated in spontaneous recurrent tumors in GEM
models, and strongly associated with decreased recurrence risk in breast cancer patients. When taken
together with our observations that Sox5 deletion accelerates tumor recurrence in mice, we hypothesize that a
developmental program requiring Sox5 is co-opted by dormant RTCs as a mechanism to evade therapy,
survive in a dormant state, and recur. Thus, we hypothesize that upregulation of an osteochondrogenesis-like
program requiring Sox5 promotes tumor dormancy following therapy, and that subsequent downregulation of
Sox5 activity promotes tumor recurrence by inducing the re-entry of dormant tumor cells into the cell cycle.
 The specific aims of this proposal are to: (1) Define Sox5/osteochondrogenic pathway activity in residual
disease and recurrence. Sox5-related pathway activity will be evaluated in primary and recurrent tumors,
RTCs in the mammary gland, and disseminated tumor cells (DTCs) in the bone marrow and lung in GEM
models following targeted therapy or chemotherapy. Companion studies will evaluate this pathway in bone
marrow DTCs and in residual disease in breast cancer patients following neoadjuvant therapy, and (2)
Determine the impact of Sox5 pathway modulation on residual disease and recurrence.
 This proposal will advance understanding of the role of a novel Sox5/osteochondrogenesis-like pathway in
dormant RTC survival and recurrence, thereby evaluating it as a potential therapeutic target for the prevention
of recurrent breast cancer. If successful, the ability to therapeutically target escape pathways used by dormant
residual tumor cells has the potential to prevent r...

## Key facts

- **NIH application ID:** 10990937
- **Project number:** 2R01CA098371-16
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** LEWIS A CHODOSH
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $424,531
- **Award type:** 2
- **Project period:** 2003-04-18 → 2029-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10990937

## Citation

> US National Institutes of Health, RePORTER application 10990937, In Vivo Oncogene-Induced Tumorigenesis and Escape (2R01CA098371-16). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10990937. Licensed CC0.

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