Tuesday, October 21, 2008

Neoplasms: Excerpt 9

Neoplasms: principles of development and diversity was published October 1, 2008. In the next few blogs, I will provide some short excerpts from the book.

Excerpt from CHAPTER 23 Class-Dependent Cancer Prevention, Diagnosis, and Treatment: 23.3 Why Are There So Few Tumors that We Can Now Cure?

Currently, there are just a handful of cancers that can often be cured when the cancer is discovered at an advanced stage.

Acute lymphocytic leukemia of childhood
Burkitt lymphoma
Hodgkin disease
Acute promyelocytic leukemia
Large follicular center cell (diffuse histiocytic) lymphoma
Carcinoma of testis
Hairy cell leukemia (probable)]

Today, all potential cancer cures are tested in clinical trials. The term clinical trial is virtually synonymous with prospective randomized clinical trial. Randomization refers to the random assignment of patients to the treated or to the untreated (or standard treatment) group. In addition to being randomized, many clinical trials are blinded so that neither the treating physician nor the patients know the assignment group during the trial.

Modern clinical trials are long and expensive. The process of testing a prospective new drug can take many years. For example, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO, NIH/NCI trial NO1 CN25512) serves as an example. The PLCO is a randomized controlled cancer trial. Between 1992, when the trial opened, and 2001, when enrollment ended, 155,000 women and men between the ages of 55 and 74 joined PLCO. Screening of participants and the collection of follow-up data will end around 2016. The purpose of the study is to determine whether screening will reduce mortality from prostate, lung, colon, or ovarian cancers (302). There are thousands of different tumors, and it is unlikely (actually impossible) that we will ever come up with effective, tested treatments for each and every type of cancer. Although prospective trials are considered the only way of determining the efficacy and safety of new treatments, the public may ask whether society has the time, money, and patience to continue our current course (303).

In Chapter 15, we surveyed the six major classes of neoplasms:

1. Tumors of Class Endoderm/Ectoderm
2. Tumors of Class Mesoderm
3. Tumors of Class Neuroectoderm
4. Tumors of Class Neural Crest
5. Tumors of Class Germ Cell
6. Tumors of Class Trophectoderm

The neoplasms within each class of tumor use inherited cellular pathways to achieve the neoplastic phenotype, and many of these inherited pathways are shared among the members of a tumor class. Controlling class-dependent pathways may lead to methods of cancer treatment that will be effective for most or all of the tumors within a class. We can start to think about approaches to preventing, diagnosing and treating neoplasms that are based on the range of neoplasms that occur within a neoplasm classification.

Here are 9 prioritized strategies that use class-based methods to lower the cancer death rate [discussed at length in Neoplasms]:

1. Develop of relatively nontoxic drugs that will enhance the natural tendency of precancers to regress.

2. Continue to develop strategies to prevent cancers.

3. Continue to develop effective treatments for stem cell tumors, almost all of which are tumors of childhood and almost all of which operate through simple pathways that can be targeted by relatively nontoxic drugs.

4. Continue to develop vaccines against viral carcinogens.

5. Develop epigenomic drugs that will target germ cell tumors.

6. Develop effective treatments for tumors of mesoderm, neuroectoderm, and neural crest tumors.

7. Develop effective nonsurgical treatment for benign neoplasms.

8. Develop new diagnostic and predictive markers for cancers.

9. Use experience obtained from items 1, 3, 6, and 7 to develop targeted drug treatments for endoderm/ectoderm tumors.

(to be continued)

The full Table of Contents and Index are now available from Amazon's Neoplasms book site. In the next few days, I will continue to discuss content from Neoplasms in my blogs.

-Jules Berman

Key words: tumors, tumour, neoplasms, neoplasia, carcinogenesis, tumor development, cancer research, neoplastic development, precancer preneoplasia, preneoplastic

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