That’s why it’s important to know your skin and regularly check for any changes in moles, freckles, or other skin marks, according to the American Cancer Society (ACS).

Other signs of melanoma you should watch for include:

• A bump or nodule that's scaly, lumpy, crusty, oozing, or bleeding
• Pain, itchiness, tenderness, or changes in how a mole feels
• Swelling, redness, or spread of color into the skin near a mole
• Part of a mole’s colored area that used to be flat starts to rise

Other signs of skin cancer include:

• Flat, firm areas that look a lot like a scar
• Rough or scaly red patches that might itch
• Raised growths or bumps that might be pink, red, or pearly looking
• Wart-like growths on skin that's been exposed to the sun a lot, such as your face, ears, or hands

You can remember signs of melanoma using the ABCDE rule:

• Asymmetry. One half of a mole looks different than the other.
• Border. The edges are irregular.
• Color. The color of the mole varies. It may include blue, black, brown, red, white, or pink areas.
• Diameter. The spot is larger than 6 millimeters, or the size of a pencil eraser. But some may be smaller.
• Evolving. The mole is changing. It may change in size, shape, or color.

See a healthcare provider right away if you have any of these symptoms, the ACS says.

In most cases of testicular cancer, the man has a lump on a testicle or notices that the testicle is swollen, according to the ACS. The ACS recommends that a testicular exam be included as part of a man's general health checkup. See your healthcare provider if you notice any changes in your testicles.

A change in bowel habits is a symptom of colon and rectal cancer. Other symptoms include rectal bleeding, belly (abdominal) cramping, and weight loss. Stomach cancer does not often cause symptoms early in the disease. It may cause belly pain, nausea, or a feeling of "fullness" after eating only small amounts of food.

Mammography is an important tool for finding breast cancer early, when it’s small and easiest to treat. But the benefits and limits of mammography vary based on things such as age and personal risk. Experts have different recommendations for mammography. For those at average risk, the ACS recommends yearly screening for all women ages 45 to 54. Women ages 40 to 45 have the option to start yearly mammogram screenings. Screening can continue to be done yearly, or can be done every 2 years for women ages 55 and older. Women should talk with their healthcare provider about their personal risk factors before making a decision about when to start getting mammograms and how often they should get them. All women should know how their breasts normally look and feel and report any changes to a healthcare provider.

Other possible signs are chest pain that's worse with coughing or deep breaths, and increased sputum or blood in the sputum. These symptoms could be caused by something other than cancer. But be sure to have any of these checked out by your healthcare provider.

Signs of advanced prostate cancer include trouble passing urine, back pain, trouble getting an erection, and blood in the urine or semen.

These cancers are the most common signs of mouth or tongue cancer. They are mostly found in people who smoke, chew tobacco, or both. Regular dental checkups that include a whole mouth exam can help find these cancers early, according to the ACS.

The most common symptoms are blood in the urine or changes in bladder habits, according to the ACS. These could be signs of other health problems. But be sure to tell your healthcare provider if you notice changes.