There is concern regarding injuries to moles - supposedly this contributes to their degeneration into a cancerous tumor. We decided to check whether this is supported by scientific data.

Stories of a damaged mole and subsequent cancer are not only passed on by word of mouth and spread throughout the world. blogs. The problem are interested users of question and answer services; about the presence of danger, but lack of proof of a direct connection write specialized sites, doing accent on chronic trauma. Publications about the connection between mole injuries and cancer are popular. Media various countries, from Kazakhstan to Belarus.

Moles are spots or nodules on the skin, scientifically called nevi. They are benign neoplasms arising from specific nevus cells, a subtype of melanocytes. Melanocytes, in turn, are cells that synthesize the pigment melanin, which gives the skin its color. However, ordinary melanocytes are evenly distributed in the skin, and nevus cells accumulate in the form of nests. Nevus cells, from which moles are formed, are formed during the prenatal period of human development, that is, the skin is literally “programmed” for the appearance of a nevus from birth. However, a mole can appear at any time in life - most often in childhood, adolescence or during hormonal changes, for example during pregnancy.

Skin cancer is a collective name for basal cell and squamous cell carcinoma. From a strictly formal point of view, melanoma does not belong to skin cancer, that is, tumors formed from epithelial cells, since its precursor cells are melanocytes. Although many sources, including authoritative, denote all three pathologies with the collective name “cancer”; it would be more accurate to talk about malignant neoplasms of the skin.

Basal cell carcinoma, or basalioma, is the most common oncological pathology of the skin. She is being formed from the basal cells of the epidermis, located in its lowest layer. Basalioma most often occurs on exposed areas of the body that are most exposed to sunlight - the neck, face and hands. Thus, exposure to ultraviolet radiation is the main predisposing factor occurrence of this type of cancer. Others include radiation therapy, immunosuppressive medications, arsenic exposure, and family and personal history (in about 25% of patients with one basal cell carcinoma within the next five years after the first tumor develops appears new). Basalioma is more susceptible to fair-skinned people who often get sunburned, and due to the fact that the tumor develops extremely slowly, over decades, it is usually diagnosed in older people. At the same time, this is one of the most non-aggressive tumors - it almost does not metastasize, and for its treatment most often enough removal of affected tissue with a scalpel, laser or cryodestruction method. No There is no connection between moles and basal cell carcinoma, since it is, in principle, formed from other layers of the skin.

It's a similar story with squamous skin cancer, the second most common type of skin malignancy. It occurs during the degeneration of flat cells located in the middle and upper layers of the epidermis. Squamous cell carcinoma, like basal cell carcinoma, is more often arises on exposed areas of the skin, but can also develop in areas that are not normally exposed to sunlight, such as the mouth, soles of the feet, or genitals. In addition to exposure to ultraviolet radiation from the sun or tanning bed, a number of other skin diseases contribute to the development of squamous cell skin cancer (actinic keratosis or Bowen's disease), a weakened immune system (for example, in people with leukemia or lymphoma or those taking immunosuppressive drugs after an organ transplant), the presence of the human papillomavirus, and the rare genetic disease xeroderma pigmentosum. Light skin, male gender and age over 50 also include to risk factors. Squamous cell carcinoma is also quite non-aggressive a tumor that rarely metastasizes and responds well to treatment. There is also no link between trauma to a mole and squamous cell carcinoma, but there is a link between this type of cancer and skin lesions. Marjolin's ulcer, a subtype of squamous cell carcinoma, forms at the site of chronic injury or scarring (for example, after a burn). Although this process is extremely long (transformation occurs on average about 30 years), it is quite aggressive. Reborn Marjolin's ulcer can be scars from any violation of the integrity of the skin - heat burns, surgical interventions, animal bites and even injections. Science does not yet know the exact cause of the malignant process. Presumably, the injury disrupts the local blood and lymphatic vessels, which makes this area immune-privileged and protects the scar from antitumor antibodies. In general, we can assume the following situation: an area of skin with a mole located on it was subjected to a thermal burn, and then a scar formed there, which decades later turned into a Marjolin’s ulcer. However, it would be wrong to say that it was the mole that became the trigger for cancer in this case.

Finally, the third type of skin malignancy is melanoma. It does not arise from epithelial cells, but from melanocytes. It would be logical to assume that areas of accumulation of melanocytes (that is, nevi) most often become a “platform” for the development of melanoma. However, this is not so - only third In all cases, melanoma occurs when a mole degenerates; in other cases, melanoma appears on “clean” skin when an individual melanocyte degenerates into a malignant tumor. By statistics, the transformation of a nevus into melanoma occurs per year in less than one case per 200,000 people under 40 years of age. After this age, the risk increases, especially for men (about one case per 33,000 over 60 years of age). The overall lifetime risk of any mole developing into melanoma is 0.03% for men and 0.009% for women.

Unlike basal cell and squamous cell carcinoma, melanoma is more aggressive tumor. When it is detected at the first stage, 98% of patients live longer than five years, but in the fourth stage, only half overcome the six-year mark, and only when receiving combination immunotherapy.

As is the case with basal cell and squamous cell carcinoma, the main factor melanoma risk - exposure to ultraviolet radiation. Moreover, not only natural sunlight, but also a solarium has a negative impact. Sunburn as a child or teenager also increases this risk. PUVA therapy (a method of treating psoriasis by applying a photoactive substance to the skin followed by ultraviolet irradiation) also increases risk of developing the disease. In addition to exposure to UV rays, risk factors applies a weakened immune system, fair skin with large and atypically shaped moles, as well as a genetic predisposition. Injuries to both the skin as a whole and individual moles among factors There are no risks.

In addition to these three fairly common malignant skin tumors, there are a number of others. For example, Merkel cell carcinoma arises from neuroendocrine Merkel cells, evenly distributed in the skin and outer layers of the hair follicle (around the hair roots). She meets very rare, ranging from 0.13 to 2.5 cases per 100,000 people per year, with the highest incidence rates observed in Australia and New Zealand. Risk factors for this pathology are age over 65 years, ultraviolet exposure, organ transplantation, leukemia, HIV infection and infection with a special pathogen, Merkel cell polyomavirus.

The situation is similar with other malignant neoplasms that can appear on the skin - they are in no way connected with moles. Thus, Kaposi's sarcoma is a vascular tumor, the development of which is associated with the human herpes virus type eight (HHV-8), and it most affects people after organ transplantation and those with AIDS. Scientists have not yet established the exact cause of skin lymphomas - tumors from cells of the immune system. It is likely that their development is facilitated by immunosuppressive conditions (HIV infection, taking medications against autoimmune diseases). Dermatofibrosarcoma protuberans forms in connective tissue cells, cause its origin is also unknown - scientists are inclined to believe that a chromosomal mutation plays a decisive role.

Cell biologist Philip Niethammer of Memorial Sloan Kettering Cancer Center admits, that even as a child I heard warnings about the dangers of injury to a mole due to its risk of turning into cancer. He says studies in zebra fish and mice have shown that repeated trauma accelerates the development of cancer in that area. The fact is that inflammation that occurs due to injury “attracts” immune cells to this area. These same cells can “feed” the malignant process. In a number of “human” cancers, the role of inflammation has already been proven - for example, it becomes a risk factor for cancer direct intestines and stomach. However, in both animals and humans, research shows that the risk factor is not a one-time event, but chronic inflammation or repeated injury. However, in 2018, scientists from the Massachusetts Institute of Technology showedthat even a single surgical intervention and subsequent recovery processes can awaken a dormant mammary tumor in mice. However, it is impossible to transfer data from mice to humans, from breast cancer to malignant skin tumors, and surgery to a household injury to a mole without additional research. Finally, Niethammer points out that there is not a single documented case of cancer resulting from a scratched or otherwise damaged mole.

Can assumethat the myth about the degeneration of a traumatized mole into a malignant neoplasm of the skin arose due to the fact that it is difficult for a non-specialist to visually distinguish the early stage of melanoma from a mole. Melanoma often bleeds from the slightest impact, in which case a person may need to see a doctor. When a patient receives a disappointing diagnosis, he sometimes associates it with trauma and makes the incorrect conclusion that this was the cause of the disease.

Thus, there is no reason to believe that simple trauma to a mole leads to its degeneration into a malignant formation. Most types of cancer and other cancers that occur on the skin are not related to moles at all, but to exposure to ultraviolet light, which is why it is so important to protect the skin from overexposure to the sun. Some connection with moles can be traced only in melanoma, while two thirds of cases still occur on skin without nevi. And even melanomas caused by the degeneration of nevi are not associated with their injuries. However, at an early stage, only a specialist can distinguish melanoma from a mole, so if the damage does not heal for a long time, it is better to consult a doctor.

Cover image: New Port Beach. Dermatology and Plastic surgery