Cancer is any of a vast range of diseases characterized by the formation of abnormal cells that divide uncontrollably and have the ability to invade and destroy normal human tissue. Cancer has the power to spread throughout the body. Cancer is the second-largest cause of mortality worldwide. However, many types of cancer are seeing an increase in survival rates as cancer screening, therapy, and prevention improve.
Causes
Cancer is caused by changes (mutations) in the DNA of cells. The DNA inside a cell is divided into a vast number of distinct genes, each of which includes a set of instructions that tell the cell what functions to execute as well as how to grow and divide. Errors in the instructions can cause the cell to stop functioning normally and perhaps lead to cancer.
Symptoms
Some general signs and symptoms associated with, but not limited to, cancer include:

• Fatigue
• A lump or thickening that can be felt beneath the skin.
• Weight changes, including unintentional loss or gain.
• Skin changes, such as yellowing, darkening, or redness of the skin, non-healing sores, or changes to existing moles
• Bowel or bladder habits change.
• Persistent cough or difficulty breathing
• Difficulty in swallowing
• Hoarseness of voice
• Persistent indigestion or pain after eating
• Persistent, unexplained fever or night sweats.
• Bleeding from the mouth, in cough, anal region, or postmenopausal vaginal bleeding

Warning Signs of Cancer
If you notice any of these symptoms, see your doctor. Here are some probable cancer symptoms:

• Change in bowel or bladder habits.
• A sore that will not heal
• Unusual bleed or discharge
• Thickening or lumps in the breast or elsewhere
• Indigestion or trouble swallowing
• An obvious change in a wart or mole
• Nagging coughing or hoarseness

Again, if you have any of these cancer symptoms, please contact a specialist to set up an examination and screening.
When to see a doctor?
Make an appointment with your doctor if you notice any persistent signs or symptoms that concern you. If you have no signs or symptoms but are concerned about your risk of cancer, talk to your doctor. Inquire about which cancer screening tests and procedures are right for you.
Risk factors
While doctors have a concept of what causes cancer, the majority of malignancies occur in patients who have no recognized risk factors. Factors that raise your risk of cancer include:

• Age
• Habits
• Family history
• Health conditions
• Environment

Conclusion
While cancer does not typically cause apparent symptoms in its early stages, it is critical to be aware of these warning signals. Many of the indicators described above could be caused by non-cancerous diseases, but it's always a good idea to be cautious. Regular checkups, screenings, and paying attention to changes in your body are the most effective ways to detect cancer early. Early detection can greatly improve the likelihood of effective treatment and recovery. If you observe any of these symptoms or sense anything weird in your body, don't hesitate to contact your healthcare professional for a thorough evaluation and peace of mind