Li-Fraumeni syndrome

Li-Fraumeni syndrome is a rare autosomal dominant hereditary disorder. It is named after Frederick Pei Li and Joseph F. Fraumeni, Jr., the American physicians who first recognized and described the syndrome. Li-Fraumeni syndrome greatly increases susceptibility to cancer. The syndrome is linked to germline mutations of the p53 tumor suppressor gene, which normally helps control cell growth. Mutations can be inherited or can arise de novo early in embryogenesis or in one of the parent's germ cells.

Persons with LFS are at risk for a wide range of malignancies, with particularly high occurrences of breast cancer, brain tumors, acute leukemia, soft tissue sarcomas, bone sarcomas, and adrenal cortical carcinoma.

Characteristics
What makes Li-Fraumeni Syndrome unusual is that
 * several kinds of cancer are involved,
 * cancer often appears at a young age
 * cancer often appears several times throughout the life of an affected person.

Diagnosis and treatment
Li-Fraumeni Syndrome is diagnosed if the following three criteria are met:
 * 1) the patient has been diagnosed with a sarcoma at a young age (below 45),
 * 2) a first-degree relative has been diagnosed with any cancer at a young age (below 45),
 * 3) and another first-degree or a second-degree relative has been diagnosed with any cancer at a young age (below 45) or with a sarcoma at any age.

Genetic counseling and genetic testing are used to confirm that somebody has this gene mutation. Once such a person is identified, early and regular screenings for cancer are recommended for him or her. If caught early the cancers can often be successfully treated. Unfortunately, people with Li-Fraumeni are likely to develop another primary malignancy at a future time.

Pathology

 * LFS1: The TP53 (tumor suppressor gene p53) normally assists in the control of cell division and growth through action on the normal cell cycle. TP53 assists in repair or destruction of "bad" DNA before it can enter the normal cell cycle, thus preventing abnormal and/or cancerous growth of cells. Mutations of TP53 prevent this normal function and allow damaged cells to divide and grow in an uncontrolled, unchecked manner forming tumors (cancers). TP53 mutations have been primarily implicated in Li-Fraumeni.


 * LFS2: A variant of Li-Fraumeni does not have a mutation in TP53 but instead has mutation of the CHEK2 (or CHK2) gene. CHK2 is also a tumor suppressor gene. The complete implication of this mutation is not known, but CHK2 regulates the action of p53. CHK2 is activated by ATM which detects DNA damage, and in this way DNA damage information can be conveyed to p53 to indirectly arrest the cell cycle at that point for DNA repair to be able to take place or to cause apoptosis (programmed cell death).