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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Malignancy | 1/2 | https://en.wikipedia.org/wiki/Malignancy | reference | science, encyclopedia | 2026-05-05T07:30:28.374982+00:00 | kb-cron |
Malignancy (from Latin male 'badly' and -gnus 'born') is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A malignant tumor contrasts with a non-cancerous benign tumor in that a malignancy is not self-limited in its growth, is capable of invading into adjacent tissues, and may be capable of spreading to distant tissues. A benign tumor has none of those properties, but may still be harmful to health. The term benign in more general medical use characterizes a condition or growth that is not cancerous, i.e. does not spread to other parts of the body or invade nearby tissue. Sometimes the term is used to suggest that a condition is not dangerous or serious, although this is not always the case. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis. Malignant tumors are also characterized by genome instability: cancers, as assessed by whole genome sequencing, frequently have between 10,000 and 100,000 mutations in their entire genomes. Cancers usually show tumour heterogeneity, containing multiple subclones. They also frequently have reduced expression of DNA repair enzymes due to epigenetic methylation of DNA repair genes or altered microRNAs that control DNA repair gene expression. Tumours often manifest as a visible lump on the body. A mammogram or MRI scan can be used to determine or detect a suspected tumour, particularly if there is no visible lump. If an apparent tumour is detected, a biopsy—examination of a small sample of the tissue in a laboratory—is required to make a definitive diagnosis, and distinguish whether the tumour is malignant or benign. Malignant, and some benign, tumours usually require treatment, which is most effective at an early stage of tumour development. Treatment may be by chemotherapy, surgery, ionising radiation, hyperthermia, and other means.
== Signs and symptoms == When malignant cells form, symptoms do not typically appear until there has been a significant growth of the mass. Once signs and symptoms do arise, they are dependent on the location, size and type of malignancy. Usually, it is quite general and can be associated with other illnesses or diseases and thus, can be difficult to diagnose or can be misdiagnosed. Signs include observable or measurable aspects such as weight loss (without trying), a fever or unusual bleeding. On the other hand, symptoms are felt internally by the individual such as fatigue or changes in appetite. A general list of common signs and symptoms includes pain (headaches or bone aches), skin changes (new moles or bumps), coughing and unusual bleeding. There are also signs and symptoms specific to females including belly pain and bloating or breast changes i.e., the formation of a lump. Signs and symptoms specific to males include pain or growths in the scrotum or difficulty urinating.
== Causes == Malignant cells often evolve due to a combination of reasons rather than one definitive reason. Reasons which can explain their development include genetics and family history, triggers such as infectious diseases, and exposure to risk factors.
=== Triggers === Infectious diseases play a role in the development of malignancy, with agents of infectious disease being able to produce a multitude of malignant cells. These include bacterial causes, fungal and parasitic causes, and viral causes. Bacteria, fungi and similar pathogens have the ability to form an environment within states of chronic inflammation which gives rise to oncogenic potential. Viral agents are able to assist the formation of malignant tumours due to a mechanism of cell transformation. This cell transformation can occur through either "DNA integration or cellular-DNA alteration of growth regulator genes". Inflammation can also play a role in triggering malignancy as it can promote stages of tumour formation. The main purpose of inflammation is to repair tissue, defend the body against pathogens and regenerate cells. At the same time, inflammatory cells can also interact with malignant cells to form an inflammatory tumour microenvironment. This environment increases the likelihood of forming malignant cells through blockage of anti-tumour immunity. Once this occurs, the inflammatory tumour microenvironment begins to send out tumour-promoting signals to epithelial cells, triggering the formation of malignant cells.
=== Risk factors === Traditional risk factors of developing malignancy include smoking, sun exposure, and having a history of cancer in the family. Other risk factors include developing post-transplant malignancy which occurs subsequent to solid organ transplantations.
==== Post-transplant malignancy ==== Individuals who undergo organ transplant surgery have an increased risk of developing malignancy in comparison to the general population. The most common form of malignancy being "nonmelanoma skin cancer and posttransplant lymphoproliferative disorders". The different types of malignancy developed post-transplant depend on which organ was transplanted. This is linked to recipients being at a higher risk when exposed to traditional risk factors as well as, the type and intensity of the operation, the duration of their immunosuppression post-operation, and the risk of developing oncogenic viral infections.
== Management == There are various treatment forms available to help manage malignancy. Common treatments include chemotherapy, radiation, and surgical procedures. Photoradiation and hyperthermia are also used as treatment forms to kill or reduce malignant cells. A large portion of patients are at risk of death when diagnosed with malignancy as the disease has usually progressed for a number of years before detection.