# PROLIFERATIVE LIFESPAN OF MAMMARY EPITHELIAL CELLS

> **NIH NIH R01** · BARBARA ANN KARMANOS CANCER INSTITUTE · 1987 · $94,167

## Abstract

The overall objective of these studies is to examine the alterations in
cellular growth control that occur during neoplastic transformation of rat
mammary epithelial (RME) cells.  The working hypothesis is that normal
cells have a finite proliferative lifespan and that an important alteration
in cellular growth potential occurs during cancer development which results
in the acquisition of an enhanced, perhaps indefinite, proliferative
lifespan.  Acquisition of this enhanced proliferative potential is
necessary but insufficient for complete neoplastic transformation and
therefore represents a truly preneoplastic phenotype.  The experiments will
employ a newly developed culture system in which normal RME cells undergo
15 to 20 population doublings over 4 to 5 in vitro passages before
exhibiting signs of senescence.  This culture system will be used; a) to
examine the hormone and growth factor requirements that induce long term
proliferation of normal RME cells in vitro, b) to isolate populations of
preneoplastic cells from mammary tissues of carcinogen treated rats and
populations of neoplastic cells from mammary carcinomas based on their
enhanced proliferative lifespan, 3) to examine the hormone and growth
factor requirements of preneoplastic and neoplastic RME cells relative to
those of normal RME cells in vitro.  These studies address the mechanisms
of the alterations in growth control that occur in RME cells during the
stepwise acquisition of enhanced proliferative potential and neoplastic
potential.

## Key facts

- **NIH application ID:** 3179517
- **Project number:** 5R01CA040064-03
- **Recipient organization:** BARBARA ANN KARMANOS CANCER INSTITUTE
- **SAM.gov UEI:** NAJZPZ4GN5B3
- **Principal Investigator:** STEPHEN P. ETHIER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $94,167
- **Award type:** 5
- **Project period:** 1985-07-01 → 1988-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3179517

## Citation

> US National Institutes of Health, RePORTER application 3179517, PROLIFERATIVE LIFESPAN OF MAMMARY EPITHELIAL CELLS (5R01CA040064-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3179517. Licensed CC0.

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