What liver cancer is
The liver is the body's filter and factory — it cleans toxins out of the blood, stores energy for later, and makes proteins the body needs, including the ones that help blood clot. It's built from billions of tiny cells, each following a "rulebook" (DNA) that says when to grow, divide, and stop.
Cancer happens when a few liver cells stop following that rulebook. They copy themselves over and over without stopping, piling into a lump called a tumor.
What is Hepatoblastoma
Hepatoblastoma itself is rare to begin with — it's diagnosed in roughly 1 in a million children. Even within that small group, the disease covers a wide range. Some tumors are caught early, confined to one part of the liver, and can be cured with surgery alone or a shorter, more contained course of chemotherapy. Others are larger, involve more of the liver, or have already spread, and need much longer, far more intensive treatment. Doctors use imaging, staging, and markers like AFP to sort a tumor into a risk category, which is what actually determines how aggressive treatment needs to be. Most hepatoblastoma shows up in young children under 5.
Hepatoblastoma with Carcinoma Features - HBC — a subtype that behaves differently
When hepatoblastoma happens in an older child, doctors sometimes find other types of cells mixed into the tumor — cells that look more like a different, more aggressive liver cancer that usually shows up later, in older kids and adolescents.
Doctors call this "hepatoblastoma with carcinoma features" (HBC), but this name is provisional and may change. Pathology reports may also use other terms, such as HCN-NOS (hepatocellular neoplasm, not otherwise specified). That doesn't mean two separate cancers — the tumor is still mostly hepatoblastoma, with some of that different, more aggressive type of cell mixed in.
Because of those other, more aggressive cells, this isn't treated as routine hepatoblastoma. It's a rarer, higher-risk, genuinely harder cancer to treat — usually needing a longer and more intensive combination of therapies (different types of chemotherapy, surgery, or transplant) than the standard plan, not just closer watching. It's also considerably rarer than hepatoblastoma itself, which is already rare: published literature on this specific form is still built mostly from small case series, just a few dozen documented cases worldwide, rather than large population data.
Hepatocellular Carcinoma HCC
HCC, or hepatocellular carcinoma, is the most common liver cancer in adults, usually linked to long-term alcohol use, hepatitis infection, or fatty liver disease. In children it's extremely rare — and when it does happen, it's spontaneous, not caused by those same lifestyle factors.
HCC is difficult to treat with chemotherapy and typically requires a liver transplant.
Hepatoblastoma and HCC are two distinct liver cancers, usually diagnosed in very different age groups. HBC sits on a spectrum between them — a tumor that's mostly hepatoblastoma, mixed with cells that resemble HCC — which is part of why it's such an unusual and understudied combination.
Biopsy — how the diagnosis is confirmed
Scans and AFP levels can strongly suggest hepatoblastoma, but a biopsy is how the diagnosis is confirmed. A biopsy is a small sample of the tumor, examined under a microscope by a pathologist — a doctor who specializes in diagnosing disease from tissue.
How it's done
It's usually done by an interventional radiologist, a doctor who specializes in image-guided procedures. Using ultrasound to see the tumor, they guide a thin needle through the skin to collect a few tiny samples of tissue. In children it's usually done under anesthesia, before chemotherapy starts.
What the pathologist looks for
The diagnosis itself: confirming it's hepatoblastoma and not another type of liver tumor, including HCC.
Cell types: which types of cells make up the tumor, including whether other, more aggressive cells are mixed in, as in HBC.
Tissue for testing: the sample can also be used for the genomic testing described below.
A needle biopsy just takes a small sample, so it may not capture every cell type. After surgery or transplant, a pathologist can examine the whole tumor or liver.
Genetic Mutations
What is a mutation
A mutation is a change in a stretch of DNA — a typo in the instructions a cell follows. Most mutations do nothing noticeable, or get repaired. But some land somewhere that changes how a cell behaves, and if that change lets a cell divide when it shouldn't, it can help drive cancer.
How to identify a mutation - Genomic tumor testing
A genomic panel test reads the DNA inside a tumor sample, checking a set list of genes already known to matter in cancer for mutations, extra copies, or other changes that might explain how a specific tumor is behaving — and, sometimes, point toward a treatment option. Different hospitals and labs run their own versions of this kind of test, built around slightly different gene lists.
Example of a genomic test: the UCSF500
Here's what one such test, the UCSF500, actually does: it checks about 500 cancer-related genes, comparing the tumor's DNA to a sample of normal, healthy tissue, usually blood or saliva.
Tumor vs. normal tissue
That comparison is the key:
Somatic mutation: a change found only in the tumor sample, not in the normal sample, happened inside the cancer cells themselves. It's a somatic (acquired) change, not something present everywhere in the body.
Germline mutation: a change found in both samples is a germline (inherited) change, present from birth.
Running the tumor against normal tissue is how doctors can say with confidence that a specific change found in the tumor is tumor-only, not inherited. The test also helps confirm the exact tumor subtype, flag mutations linked to more aggressive behavior, and check whether any changes point toward a treatment option.
Common mutations in HBC
The majority of HBC cases are driven by a somatic mutation — an acquired, random change in the tumor's DNA, not something inherited. These mutations exist only inside the tumor cells, not the rest of the child's body, and can't be passed to a future child.
CTNNB1 — the mutation that often starts it
Virtually every hepatoblastoma, including HBC, starts with a mutation like this. The vast majority — over 90% — involve a gene called CTNNB1, which switches on a growth signal (the Wnt pathway) that tells liver cells to keep dividing when they normally wouldn't. That's the mutation that actually starts the cancer.
TERT — the mutation that keeps cells dividing
TERT promoter mutations are a separate, additional change layered on top of the CTNNB1 mutation, seen mainly in older children with HBC rather than typical infant hepatoblastoma. Every time a cell divides, the tips of its DNA (telomeres) get a little shorter, and normal cells eventually run out and stop dividing — a built-in safety brake. A TERT promoter mutation flips that switch to "on," so tumor cells never run out and never stop dividing.
Think of telomeres, the tips of DNA, like a strand of spaghetti: each division takes one bite off the end, and eventually there's not enough left to bite. TERT is like a machine that splices on a fresh bit after every bite, so the cell never has to stop dividing.
Metastasis — how cancer cells travel
A tumor isn't a frozen lump. Individual cells inside it can break away and slip into nearby blood or lymph vessels — the highways that carry blood and fluid through the liver and out to the rest of the body. If a cell survives that trip and starts dividing somewhere else — a lung, a lymph node, another part of the liver — that's metastasis: the same cancer, now growing in a second spot.
How it differs from an infection
This is still fundamentally different from an infection spreading through the bloodstream inside the same body — like a bacterial infection that seeds new sites in different organs. An infection is caused by something foreign: bacteria or a virus, with its own genetic material, multiplying on its own or hijacking cells to copy itself. The immune system recognizes that foreign material and mounts a response — inflammation, fever, white blood cells rushing in.
A metastasizing cancer cell isn't foreign. It's the patient's own cell, carrying the patient's own DNA, just with broken growth controls. Because it still reads as "self," the immune system often doesn't flag it the way it flags an infection.
That difference also shapes treatment. Antibiotics can target something foreign in a bacterium without touching the patient's own cells. A chemo drug fighting the patient's own runaway cells has a much harder time telling them apart from healthy ones — part of why chemo affects the whole body the way an antibiotic doesn't.
What AFP is
AFP stands for alpha-fetoprotein, a protein made by immature liver cells — the kind present before birth. As liver cells finish developing, the gene that produces AFP normally switches off, and levels drop to nearly zero. That timing is just background biology; it has nothing to do with what caused this cancer.
Hepatoblastoma cells are called "blast" cells — the same word the disease is named for — because the mutation driving them locks them into an immature state, similar to how liver cells look before they're fully developed. Because of that, many hepatoblastoma tumor cells keep making AFP, the way an immature liver cell would.
Doctors can use AFP to help diagnose the tumor, check whether treatment is shrinking it, and watch for relapse afterward — a level that starts climbing again, even before anything shows up on a scan, can be an early warning sign.
Relapse & microscopic disease
A relapse is cells that survived treatment — whether still at the original site or already moved to a different spot — too small to detect at the time, sometimes called "cancer dust," that later grow into a tumor doctors can see. This is why blood markers (like AFP) and scans get checked on a schedule for months or years after treatment ends — to catch it as early as possible.
Why detection has limits
Treatment aims to remove or kill everything that can be detected. But detection has real limits at every stage:
During surgery, special dyes that make tumor cells glow under a particular light typically can't reliably show anything smaller than a few millimeters, or more than about a centimeter deep in tissue.
Scans — MRI, CT, or PET, even with contrast — can't detect truly microscopic disease either.
What scans can and can't catch
Routine CT and MRI scans reliably catch tumors down to about half a centimeter to a centimeter (5–10 mm) — roughly pea-sized or a little smaller. Detection gets much less reliable below that; in studies of small liver tumors, scans caught only a small fraction of spots under 5 mm. True microscopic disease is smaller still — clusters of a few thousand to a few million cells — nowhere near visible on any scan available today.
Cells can lie dormant for years
Cells too small to detect can also sit inactive for years instead of growing right away. A tiny cluster has no blood supply of its own — it's too small to have grown the network of vessels a bigger tumor needs — so without enough oxygen and nutrients to divide, it settles into a resting state called dormancy.
In that state, cells stop dividing, use very little energy, and don't produce much of anything a blood test would catch — which is why AFP can come back completely normal even with a few dormant cells still present. Only once new blood supply reaches that spot do they wake up and start dividing again, sometimes years later.
What chemotherapy is
Chemotherapy is medicine built to kill fast-dividing cells, which is what cancer cells do. It travels through the bloodstream, reaching cancer cells anywhere in the body, not just the main tumor.
That's called systemic treatment — "systemic" means throughout the whole body, unlike local treatment (surgery, radiation), which only affects one spot.
Why go systemic instead of just removing the visible tumor? Because of the "cancer dust" problem: cells too small to see on a scan may already have traveled elsewhere through blood or lymph. Surgery alone can miss those; chemo circulates everywhere blood goes.
How chemo gets into the body. Chemo is hard on smaller veins, so repeated doses are usually given through a port — a small device implanted under the skin, often in the chest, connected to a large vein. It stays in place between treatments and is accessed with a needle when needed, avoiding a new IV each visit. Because it sits fully under the skin, a port carries a lower infection risk than an external line. Any fever during chemo still has to be treated as a possible infection and evaluated right away, and the port has to be accessed and cared for with strict sterile technique every time.
What a cycle is. Chemo isn't given as one continuous treatment — it's broken into cycles (also called treatment blocks or courses): a period of active treatment followed by a rest period before the next one starts. A cycle might run 14, 21, or 28 days depending on the protocol and risk group — chemo is given on just a few of those days (say, days 1, 8, and 15), with the rest as recovery time for the body, especially fast-recovering tissue like bone marrow.
These schedules come from established international protocols, like SIOPEL and the current PHITT trial, which set the standard treatment plans used around the world. A full treatment plan usually strings together several cycles, with scans and blood tests along the way to check how the tumor is responding.
Why not a targeted drug instead? Targeted therapies lock onto one specific feature of cancer cells and leave most normal cells alone, so they're often gentler. But they only work when a tumor has a clear, "druggable" target a drug exists for. Hepatoblastoma, especially the HBC form, doesn't yet have a well-established targeted option — the biology isn't understood well enough, and there isn't strong evidence a targeted drug alone would control it. Systemic chemo, often paired with surgery, remains the approach with the most evidence behind it for this cancer.
Why chemo makes the body feel so sick
Chemo can't perfectly tell a cancer cell apart from a healthy cell that just happens to divide quickly too. Hitting those healthy fast-dividing cells causes most of the classic side effects.
Nausea: chemo irritates the stomach lining and also triggers a "vomiting center" in the brain directly. That's why anti-nausea medicine is usually given alongside chemo, before symptoms start.
Hair loss: hair follicle cells divide very quickly, which is how hair grows, so they're one of the most affected healthy groups. Hair usually grows back after treatment ends.
Neuropathy: some chemo drugs irritate or damage nerves, especially in hands and feet, causing tingling, numbness, or pain. Nerve cells rely on long internal "cables" that some drugs interfere with.
Mucositis: chemo also damages the fast-dividing cells lining the mouth and gut, causing inflammation and painful sores called mucositis. It can make eating, drinking, or swallowing hard, and sometimes needs its own pain management or nutrition support.
Fatigue: repairing all of that damage, plus the bone marrow's own recovery, takes energy — which shows up as tiredness and general achiness, even without any one specific cause.
Feeling sick isn't a sign the treatment is failing — it's usually a sign the medicine is actively affecting fast-dividing cells, which is the mechanism doctors are counting on.
Some chemo drugs used for this cancer can also affect specific organs over the longer term, including hearing, kidney function, and heart function. That's why hearing tests, kidney function labs, and heart imaging are built into the treatment and follow-up schedule — to catch and manage any changes early, not because they're expected to happen to every child.
Neutropenia and the Neulasta shot
Bone marrow, where blood cells are made, is also full of fast-dividing cells, so chemo affects it too — not just one type, but every type it produces:
Platelets: help blood clot. Low counts mean easier bruising and bleeding.
Red blood cells: carry oxygen. Low counts cause the fatigue and paleness of anemia, sometimes needing a transfusion.
Neutrophils (ANC): a white blood cell that's the body's first line of defense against infection.
Neutropenia means the neutrophil count has dropped very low, sometimes close to zero — essentially no immune defense left. At that point, even the ordinary bacteria that normally live harmlessly on a person's own skin and gut can turn dangerous, and there's almost no buffer against viruses or germs that other people, even a healthy sibling or visitor, can pass along without meaning to or knowing it. That's why a fever during chemo is treated as an emergency, and why temperatures get watched closely between treatments.
A Neulasta (pegfilgrastim) shot gives the body a copy of a natural signal that tells bone marrow to make neutrophils faster, helping the count recover sooner after a chemo cycle.
Why it's painful: Neulasta revs up bone marrow production, and bone marrow lives inside bones. That increased activity, especially in the long bones, hips, and lower back, is what causes the deep, aching bone pain some people feel after the shot. It's a side effect of the marrow doing exactly what the shot tells it to do, not a sign something is wrong.
Local control: why the chemo has to actually work
"Local control" means eliminating the cancer at the original site, not just shrinking it. In hepatoblastoma treatment, chemo is often given first to shrink the tumor, then surgery (or sometimes liver transplant) removes what remains.
Chemo has to work well enough to make that surgery possible and complete. If it only partially shrinks the tumor, or if the tumor sits somewhere surgery can't safely reach, local control becomes much harder — and without it, the tumor itself keeps seeding new "cancer dust," no matter how well the systemic treatment is doing elsewhere.
That's why doctors track both at once: how well the body-wide treatment is working, and whether the plan will fully remove the tumor site itself.
Why cancer can respond, then come back
Chemo often works well at first — the tumor shrinks, markers like AFP drop. But cancer cells aren't all identical; a tumor holds many slightly different cells, some more vulnerable to a given drug than others.
When chemo kills the vulnerable cells, it can leave behind a smaller number that happened to be naturally tougher against that drug, the way spraying a garden doesn't kill every weed evenly. Those survivors can multiply and regrow, and because they were selected for toughness, they respond less well to the same drug a second time. This is resistance, and it's part of why a relapse is sometimes treated with a different chemo combination.
A transient response is a tumor that shrinks at first but doesn't stay shrunk, either because a few resistant cells regrew or because a good early response wasn't followed by full local control. It isn't a sign anyone did anything wrong. It reflects how varied cancer cells can be, and it's why treatment plans get adjusted based on how a tumor actually behaves, not just the standard first-line plan.
Remission, NED, and surveillance
Remission means the signs of cancer have gone down or disappeared — the tumor has shrunk on scans, or markers like AFP have dropped to normal. It describes a response to treatment, not a guarantee that every cancer cell is gone.
NED, or "no evidence of disease," is what doctors say when scans and blood markers come back clean after treatment ends. It's the best status achievable with current tools — but as the cancer dust and dormancy sections above explain, it means nothing detectable was found, not that every last cell is confirmed gone. Many people who reach NED are cured; some aren't, which is exactly why the next stage matters.
Many hospitals mark the end of active chemotherapy with a small ritual: ringing a bell. It marks finishing treatment.
Surveillance is that next stage: a schedule of follow-up blood tests and scans, spaced out over months and then years, built specifically to catch a relapse as early as possible if one happens. It's the standard, expected process after treatment for this kind of cancer, and it's how cancer dust gets caught before it grows into something visible.
The 5-year mark is the standard benchmark used across oncology — it's why oncologists watch patients closely throughout that stretch, with regular checkups, MRI or CT scans, and AFP lab draws. The risk of relapse generally goes down the further out a child gets from treatment, which is why five years has become a meaningful checkpoint. Reaching it is a strong sign of durable remission, though not a guarantee — surveillance often continues beyond it, especially for higher-risk cases like HBC.
Common misconceptions
"Did I cause this — is it something I did, or something I exposed my child to?" No. It's a mistake that happened inside a few cells while the liver was still developing, not something a child did or a parent's fault. It's also a different disease than the liver cancer most people picture in adults, which is often linked to long-term alcohol use, hepatitis infection, or fatty liver disease — none of that applies here.
"Is it like an infection — can it spread to other family members?" No. Cancer can't spread person to person through contact — hugging, sharing food, being in the same room. It isn't a germ and can't be caught.
"Is it hereditary — did it come from a parent, or will it pass to future kids?" Two kinds of mutations get confused here:
Inherited (germline): present in every cell from birth, passed parent-to-child. About 5–10% of cancers overall are inherited this way. A small share of hepatoblastoma cases link to conditions like Beckwith-Wiedemann syndrome or FAP that raise risk — but even then it's the risk that's inherited, not the cancer itself, and most kids with hepatoblastoma have neither.
Acquired (somatic): like the TERT promoter mutation, happens by chance in a single cell during the child's life, exists only inside the tumor, and cannot be passed on.
Resources for further reading
Hepatoblastoma and childhood liver cancer
The HBC / HCN-NOS diagnosis
Genetic and Epigenetic Basis of Hepatoblastoma Diversity — Nature Communications
Surgical Pathology Diagnostic Pitfalls of Hepatoblastoma — Auld & Sergi, 2022
Cancer misconceptions
Chemotherapy and side effects
Disclaimer: The Hepatoblastoma Resource Network (HRN) is a community-focused platform dedicated to connecting families and sharing educational information about hepatoblastoma. Information on this website is for general educational and support purposes only and does not constitute medical advice, diagnosis, or treatment. HRN is not a healthcare provider or medical organization. Never disregard professional medical advice or delay seeking treatment because of something you have read on this website. Always consult your or your child’s oncologist or qualified healthcare team with any medical questions.
