## 2 Background
### Skin Pathologies  
Skin cancer is a type of cancer that originates in the skin cells. The skin is the body's largest organ and is composed of several layers. Skin cancer develops when the deoxyribonucleic acid (DNA) of skin cells undergoes genetic mutations (Figure 2), typically due to exposure to ultraviolet (UV) radiation from the sun or tanning beds. These mutations cause the skin cells to grow uncontrollably and form malignant tumors [19]. The most common type of cancer is basal cell carcinoma (BCC): This is the most common type of skin cancer. It usually appears as a shiny or nearly bump, often with visible blood vessels. BCC rarely spreads to other parts of the body but can cause local damage if not treated. The most aggressive type of skin cancer is melanoma and has the potential to spread rapidly to other organs, making early detection and treatment crucial. The exact causes of skin cancer remain unclear; however, exposure to ultraviolet radiation is identified as a risk factor for skin cancer. Factors that may heighten the risk of melanoma encompass:  
* Light skin color: Characterized by a reduced amount of pigment (melanin) in the skin, resulting in inadequate protection against UV rays. * Sunburns: The occurrence of one or more sunburns amplifies the risk of skin cancer. * Presence of multiple moles: an excess of 50 moles on the body can escalate the likelihood of developing melanoma. * Family history: A noteworthy likelihood of skin cancer exists if close relatives have a history of this type of cancer. * Weakened immune system: This factor has the potential to increase the risk of various types of cancer [19]. Preventive measures include practicing sun safety, such as using sunscreen, wearing protective clothing, and avoiding excessive sun exposure. Regular self-examinations and dermatological check-ups are essential for early detection and treatment. Early diagnosis and treatment significantly improve the prognosis for individuals with skin cancer. Because early detection is crucial, we included in the research another two pathologies that untreated and not monitored closely could lead to skin cancer--actinic keratosis and  
Figure 2: Skin cancer evolution. seborrheic keratosis. Actinic keratosis manifests through skin lesions that develop as a result of sun exposure over the years and most commonly appears on the face, lips, ears, forearms, scalp, neck, and hands. The disease progresses slowly and typically occurs in individuals over 40 years old, but if left untreated, it can transform into skin cancer known as squamous cell carcinoma [20]. Actinic keratosis is a skin tumor within the epidermis that predominantly occurs in adults and the elderly. These lesions, often benign and not requiring treatment, result from the benign proliferation of immature keratinocytes, forming round, flat, well-defined growths that slowly increase in thickness over time [21]. Treatment involves eliminating these growths through cryotherapy (freezing), curettage, or electrocautery. The solution lies in the early detection and analysis of skin lesions, especially skin cancers. Currently, this requires a visit to a doctor and numerous tests for a diagnosis, which can be time-consuming and challenging due to a decrease in specialists capable of providing accurate diagnoses. The proposed solution in this study involves early detection of skin cancer using artificial intelligence, particularly neural networks, to assist doctors in making precise diagnoses in a simple and accessible manner for both patients and healthcare professionals. This is achieved by providing an image of the affected area (Figure 3) [22; 23; 24; 25]. The proposed approach in this research entails leveraging artificial intelligence, particularly neural networks, for the early detection of skin cancer. This application aims to assist healthcare professionals in delivering accurate diagnoses in a straightforward and accessible manner for both patients and medical practitioners. The method involves presenting an image of the affected area.