The short answer
Most cancers fall into a few broad families named for the cell they start in: carcinomas (skin and organ linings), sarcomas (bone and soft tissue), leukemias (blood), and lymphomas (immune system).
Cancers are grouped by the type of cell where they begin.
Carcinomas start in the cells that line skin and internal organs and are the most common.
Sarcomas start in bone or soft tissues like muscle, fat, and cartilage.
Leukemias start in blood-forming tissue; lymphomas start in immune-system cells.
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The full explanation.
Named for where they start
There are more than 100 kinds of cancer. Most fall into a few broad families. The family a cancer belongs to depends on the type of cell where it began, not the organ alone. That is why two cancers in the same organ can behave very differently.
Carcinoma
Carcinomas are the most common cancers. They begin in epithelial cells. Those are the cells that make up the skin and the linings of organs and glands. Most breast, lung, colon, and prostate cancers are carcinomas.
Sarcoma
Sarcomas begin in bone or in soft tissues such as muscle, tendons, fat, blood vessels, nerves, or cartilage. They are far less common than carcinomas. They are also hard to treat, and outcomes tend to be better at cancer centers with sarcoma experience.
Leukemia
Leukemias start in blood-forming tissue, such as the bone marrow, and lead to large numbers of abnormal blood cells. They usually do not form a solid tumor you can feel.
Lymphoma and myeloma
Lymphomas begin in lymphocytes, a type of white blood cell that is part of the immune system. They often show up as swollen lymph nodes. Lymphomas fall into two main groups: Hodgkin lymphoma and non-Hodgkin lymphoma. Multiple myeloma begins in plasma cells, another immune cell. All of these are cancers of immune system cells.
Sources
Words to know
Tap any term to see what it means.
Common questions
What is a carcinoma?
A carcinoma is a cancer that begins in epithelial cells — the cells that cover the skin and line the inside of organs and glands. Most cancers, including most breast, lung, colon, and prostate cancers, are carcinomas.
What is a sarcoma?
A sarcoma is a cancer that starts in bone or in soft tissues such as muscle, fat, blood vessels, or cartilage. Sarcomas are much less common than carcinomas.
How are leukemia and lymphoma different?
Leukemia starts in blood-forming tissue such as bone marrow and usually does not form a solid lump. Lymphoma starts in lymphocytes, a type of immune cell, and often forms masses in lymph nodes.
Why does the cell type matter?
Cancers from different cell types tend to grow and spread differently and respond to different treatments, so naming the cell type helps guide care.
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Written by: Cancer ExplainedSources last checked: 2026-07-14 what this meansLast updated: 2026-08-11Next planned review: 2028-07-14
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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