Cancer - Genetic (Familial) Predisposition

© 2016            

By Keith S. Wexler, MBA, Maternal Fetal Medicine, Prenatal Diagnosis and Biotech Consultant, GENASSIST, Inc.

Paul Wexler, M.D., F.A.C.O.G., Medical Director, GENASSIST, Inc.

Clinical Professor, Department of OB/GYN, University of Colorado Health Sciences Center

Clinical Professor, Division of Genetics/Dept. of Pediatrics, Univ. of Colorado/The Children’s Hospital

Background: I was contacted by a patient who had a mother, sister and two maternal aunts with breast cancer, a maternal grandfather with colon and prostate cancer, a maternal aunt and maternal uncle with pancreatic cancer, a maternal aunt with uterine cancer and a maternal first cousin with thyroid cancer.

She wanted to know if she could be tested for the breast cancers genes to see whether or not she had a genetic (familial) predisposition for the development of breast cancer.

I suggested we consider a broader panel of cancer gene testing.

With the recent advancements of “Cancer Panels” patients are now able to decide whether or not to be screened for a variety of cancer genes.

Overview:

The search for genetic (familial) predisposition for the development of cancer is still in the infancy stage. Yet, major studies have helped identify mutations within genes which “predispose” some individuals and perhaps other family members to one or more types of cancer.

Identification of mutations known or suspected to be associated with certain types of cancers does not guarantee that the individual will get a cancer. Also, failure to identify a suspected “deleterious” (harmful) mutation does not guarantee that an individual will Not get cancer.

Occasionally, a mutation of “Unknown Clinical Significance” is found. This finding is currently being monitored by the testing laboratory but additional time and testing will be required before the “true significance” of that finding is known.

Identification of a mutation associated with an increased risk for one or more specific types of cancer may provide the healthcare provider with information to suggest a modification of the patient’s personal health habits or screening or diagnostic testing.

This can allow an earlier diagnosis of a specific cancer or provide reassurance that an individual does not have that specific cancer.

Earlier identification of a cancer may allow more successful therapy and in some cases targeted therapy with better remission and cure rates, will be offered.

Hopefully, this major shift in diagnosis and treatment will result in earlier intervention for enhanced prevention or treatment.

Analysis:

Cancer can be inherited in both genetic and non-genetic ways. Many cancers (i.e. breast, colon, ovarian) can be inherited in an autosomal dominant manner (50% risk to child if one parent carriers the “deleterious” gene).

Cancer panels looking for these cancer genes will help identify and/or help lower the risk for a genetic (familial) predisposition for the development of cancer.  

Since the cancer panels vary from laboratory to laboratory, it is important to get a detailed family analysis of all of the types of cancer in the family to decide which panel best covers the “familial” cancer(s).

Even though the number and types of specific cancer genes will continue to evolve , the patient needs to be aware that no cancer screening is 100% reliable.

Most cancers are acquired rather than being “inherited” or “familial”. Therefore, even if a family at risk is tested and the test is “negative” cancer may or may not recur in a family.

Information Optimizes Outcome