# THIOESTERASE 11 A NEW BREAST CANCER MARKER

> **NIH NIH R01** · CHILDREN'S HOSPITAL & RES CTR AT OAKLAND · 1987 · $98,983

## Abstract

Thioesterase II is a key enzyme which regulates the production of
medium-chain fatty acids in mammary gland by hydrolyzing medium-chain acyl
moieties from thioester linkage to the fatty acid synthetase.  Our studies
with rats and humans have shown that thioesterase II is expressed
exclusively in mammary epithelial cells, an observation consistent with its
role in milk fat synthesis.  Immunoreactive enzyme can be detected in human
breast epithelial cells regardless of their state of differentiation and
also in both primary and metstatic tumors of breast epithelial origin; the
enzyme is undetectable in other cell types.  Experiments with an animal
tumor model have shown that thioesterase II is present in the serum of rats
bearing a mammary epithelial tumor but is undetectable in normal serum; the
concentration in serum is proportional to tumor burden.  These results
indicate that the enzyme may be a useful marker for the identification of
human tumors of breast epithelial origin.

There are two objectives for this study:  (1)\to test the utility of
immunohistochemical thioesterase staining in the identification and
classification of human breast tumors; (2)\to determine whether
thioesterase II is also released into the serum of human patients bearing
mammary epithelial tumors and to evaluate the potential of serum testing in
human breast cancer diagnosis.  Thus, in pursuit of these aims, we will
prepare monoclonal anti-human thioesterase antibodies for use in both
immunohistochemical and enzyme-linked immunoassay procedures.  In
collaboration with several pathologists, we will optimize the
immunohistochemical test and will evaluate the specificity and efficacy of
thioesterase staining in primary breast tumors of various types and grades
and detection of metastatic tumors of breast carcinomas.  We will use an
animal tumor model and eventually human patients to determine whether serum
thioesterase levels show a reliable correlation with tumor burden and
whether a level of sensitivity can be achieved which would facilitate use
in the early diagnosis, prognosis, and followup of human breast cancer.  (1)

## Key facts

- **NIH application ID:** 3178395
- **Project number:** 5R01CA039431-03
- **Recipient organization:** CHILDREN'S HOSPITAL & RES CTR AT OAKLAND
- **SAM.gov UEI:** PMDEB5ZPQQN3
- **Principal Investigator:** STUART SMITH
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $98,983
- **Award type:** 5
- **Project period:** 1985-08-01 → 1989-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3178395

## Citation

> US National Institutes of Health, RePORTER application 3178395, THIOESTERASE 11 A NEW BREAST CANCER MARKER (5R01CA039431-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3178395. Licensed CC0.

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