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.
Choose how you want to read this
The whole article, with every detail and caution.
This page is for anyone who has heard words like carcinoma or lymphoma and wants to know what they mean. It explains the main families of cancer and where each one starts.
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
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.
Talk with a trained specialist or navigator
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Written by: Cancer ExplainedSources last checked: 2026-07-14 what this meansLast updated: 2026-08-11Next planned review: 2028-07-14
Review details and limits
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, and this 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 then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
General education. Low-risk educational or organizational content. Medical facts are cited to authoritative sources.
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.
Words to know
Tap any term to see what it means.
Knowledge check
0 of 5 answered
This self-assessment checks understanding of educational content only. It is not medical advice.
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, and this 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 then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. 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.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.