Many patients eventually develop acute myelogenous leukemia (AML). Older patients are extremely likely to develop head and neck, esophageal, gastrointestinal, vulvar and anal cancers. Patients who have had a successful bone marrow transplant and, thus, are cured of the blood problem associated with FA still must have regular examinations to watch for signs of cancer. Many patients do not reach adulthood.

The overarching medical challenge that Fanconi patients face is a failure of their bone marrow to produce blood cells. In addition, Fanconi patients normally are born with a variety of birth defects. A good number of Fanconi patients have kidney problems, trouble with their eyes, developmental retardation and other serious defects, such as microcephaly (small head).

The last major haematological complication associated with FA is bone marrow failure, defined as inadequate blood cell production. Several types of failure are observed in FA patients, and generally precede MDS and AML. Detection of decreasing blood count is generally the first sign used to assess necessity of treatment and possible transplant. While most FA patients are initially responsive to androgen therapy and haemopoietic growth factors, these have been shown to promote leukemia, especially in patients with clonal cytogenetic abnormalities, and have severe side effects, including hepatic adenomas and adenocarcinomas. The only treatment left would be bone marrow transplant; however, such an operation has a relatively low success rate in FA patients when the donor is unrelated (30% 5-year survival). It is, therefore, imperative to transplant from an HLA-identical sibling. Furthermore, due to the increased susceptibility of FA patients to chromosomal damage, pretransplant conditioning cannot include high doses of radiation or immunosuppressants, thus increased chances of patients developing graft-versus-host disease. If all precautions are taken, and the marrow transplant is performed within the first decade of life, two-year probability of survival can be as high as 89%. However, if the transplant is performed at ages older than 10, two-year survival rates drop to 54%.

A recent report by Zhang et al. investigates the mechanism of bone marrow failure in FANCC-/- cells. They hypothesize and successfully demonstrate that continuous cycles of hypoxia-reoxygenation, such as those seen by haemopoietic and progenitor cells as they migrate between hyperoxic blood and hypoxic marrow tissues, leads to premature cellular senescence and therefore inhibition of haemopoietic function. Senescence, together with apoptosis, may constitute a major mechanism of haemopoietic cell depletion occurred in bone marrow failure.

A cancer syndrome or family cancer syndrome is a genetic disorder in which inherited genetic mutations in one or more genes predispose the affected individuals to the development of cancers and may also cause the early onset of these cancers. Cancer syndromes often show not only a high lifetime risk of developing cancer, but also the development of multiple independent primary tumors. Many of these syndromes are caused by mutations in tumor suppressor genes, genes that are involved in protecting the cell from turning cancerous. Other genes that may be affected are DNA repair genes, oncogenes and genes involved in the production of blood vessels (angiogenesis). Common examples of inherited cancer syndromes are hereditary breast-ovarian cancer syndrome and hereditary non-polyposis colon cancer (Lynch syndrome).

Although cancer syndromes exhibit an increased risk of cancer, the risk varies. For some of these diseases, cancer is not their primary feature. The discussion here focuses on their association with an increased risk of cancer. This list is far from exhaustive.

Neoplasm is an abnormal growth of tissue which, if it forms a mass, is commonly referred to as a tumor. This abnormal growth (neoplasia) usually but not always forms a mass.

ICD-10 classifies neoplasms into four main groups: benign neoplasms, in situ neoplasms, malignant neoplasms, and neoplasms of uncertain or unknown behavior. Malignant neoplasms are also simply known as cancers and are the focus of oncology.

Prior to the abnormal growth of tissue, as neoplasia, cells often undergo an abnormal pattern of growth, such as metaplasia or dysplasia. However, metaplasia or dysplasia does not always progress to neoplasia. The word is from Ancient Greek νέος- "neo" "new" and πλάσμα "plasma" "formation, creation".

Neoplastic tumors are often heterogeneous and contain more than one type of cell, but their initiation and continued growth is usually dependent on a single population of neoplastic cells. These cells are presumed to be clonal – that is, they are derived from the same cell,

and all carry the same genetic or epigenetic anomaly – evident of clonality. For lymphoid neoplasms, e.g. lymphoma and leukemia, clonality is proven by the amplification of a single rearrangement of their immunoglobulin gene (for B cell lesions) or T cell receptor gene (for T cell lesions). The demonstration of clonality is now considered to be necessary to identify a lymphoid cell proliferation as neoplastic.

It is tempting to define neoplasms as clonal cellular proliferations but the demonstration of clonality is not always possible. Therefore, clonality is not required in the definition of neoplasia.