Oral cancer

Oral cancer starts in the oral mucosa, the moist layer that lines the inside of the mouth. That mucosa covers the lips, the cheeks, the gums, the hard palate (the firm part of the roof of the mouth), the floor of the mouth under the tongue, and the front two-thirds of the tongue. More than 90% of these tumors are squamous cell carcinomas. That means cancers that start in squamous cells, the flat, scale-like cells that make up the surface of that lining.

Here's what happens inside. Smoking tobacco is the biggest risk factor, because the smoke carries carcinogens, substances that can cause cancer. They damage DNA, the instruction manual every cell keeps inside it. That damage adds up over time as genetic changes, meaning changes to those instructions, and once enough of them pile up, the result is carcinoma. Picture an instruction manual where every exposure swaps out a letter or two: after enough changes, the cell stops following the original instructions. Alcohol plays a different role. It makes the mucosa more permeable, which simply means easier to get through, like a more loosely woven fabric that lets through whatever lands on it. That leaves the lining more vulnerable to those carcinogens.

So what does it look like? Early on, oral cancer can show up as patches on the lining of the mouth: white, red, or mixed, with white and red together. Once it's more advanced, it often forms a nodule, a hard, raised lump with an ulcerated surface, meaning the surface is broken open like a sore.