Qap

Chemo Secrets From a Breast Cancer Survivor

Breast Cancer Survivors

Get Instant Access

Autocrine Growth Factors

Autocrine Growth Factors

FIGURE 20-5 (A) Estrogen-mediated effects on ER+ breast cancer cells. (B) Inhibition of estrogen-stimulated growth in breast cancer cells by tamoxifen. These figures were reproduced with permission from Jordan, V. C. (1989). "Endocrine Therapy of Breast Cancer" (F. Cavalli, ed.), Vol. III. Springer-Verlag, Berlin.

FIGURE 20-5 (A) Estrogen-mediated effects on ER+ breast cancer cells. (B) Inhibition of estrogen-stimulated growth in breast cancer cells by tamoxifen. These figures were reproduced with permission from Jordan, V. C. (1989). "Endocrine Therapy of Breast Cancer" (F. Cavalli, ed.), Vol. III. Springer-Verlag, Berlin.

peptidic growth factor autocoids, and it may increase the levels of certain growth-inhibitory factors.

Biopsy of mammary cancer and subsequent measurement of steroid receptor levels can thus stage the tumor in its progression from hormone dependence to partial hormone dependence to final hormone independence when chemotherapy is often without effect. Unfortunately, the indications of measurements of steroid receptor levels in breast cancer are not always absolute. Not all of the ER+ tumors in postmenopausal women are capable of responding to hormonal therapy, and it appears that the ability of receptor to bind steroid does not ensure the complete functioning of the receptor within the cell, such as the ability to translocate to the nucleus. On the other hand, the nucleus may contain null ERs that associate with the nucleus in the absence of steroid and may represent a refractory subpopulation. There have also been indications in the literature of other mutations in the ER, and these may form a subgroup within the ER+ population of breast cancers. Clearly, more research into this area of defects in ER function is needed to sharpen prognostic ability. Some work has shown that the cellular protooncogene erbB-2 (HER 2/neu, this encodes for part of the EGF receptor) is overexpressed by some breast cancers, and its expression has been associated with low likelihood of survival in about one-fifth of a study group.

Another finding is that normal human mammary cells produce a substance(s) that specifically inhibits the growth of mammary tissue. This protein (47, 65 kDa) has been purified and an antibody has been prepared. The protein inhibits the growth of five trans-

formed human mammary cell lines without affecting transformed lines derived from tissues other than mammary cells. This is an interesting development and will be even more so if means are found to induce this activity in cancer cells.

Thus, receptor measurements may offer a more specific evaluation of a subset of patients. The continued refinement of the presence of steroid receptors and their mutants as correlated to their specific functions, together with the measurement of new indicators such as cellular protooncogenes, will greatly enhance prognosis and treatment of this disease.

BglII Hindlll

Was this article helpful?

0 0
10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment