Skip to main contentLast updated: 23-Oct-2026
Dr Harsh Shah
MS, MCh (Surgical Gastroenterology), DrNB (Surgical Gastroenterology)
Registered with Gujarat Medical Council, Reg. No. G-38738
Stomach Cancer Surgeon
Apollo Hospital, Bhat, Gandhinagar · Gota OPD, Ahmedabad · 18 years of experience
★★★★★ Google: 4.89 from 216 reviews (Gota clinic) · 4.94 from 18 reviews (Apollo, Bhat)
In short
A stomach cancer biopsy report answers two kinds of question. The first is what the cancer looks like under the microscope: its type and grade. The second is which markers it carries, and these decide which medicines can work.
Every stomach cancer should now be tested for four markers: HER2, PD-L1, MSI (also written as MMR) and Claudin 18.2. They matter most when the cancer has spread, but they should be done on the first biopsy.
The report does not give the stage, and it does not decide the operation on its own. The stage comes from the CT scan, and sometimes a keyhole look inside the abdomen.
How stomach cancer is tested, staged and treated, from the first endoscopy to the operation, is set out on the stomach cancer treatment in Ahmedabad page.
During the endoscopy, small pieces of the stomach lining are taken. A pathologist sets them in wax, cuts thin slices and looks at them under the microscope. Extra stains on the same wax block show the markers.
Most reports come in two parts. The first part arrives in a few days and confirms cancer. The marker results often follow a week or two later, as an addendum. Many families see only the first part and do not know the second is still coming.
Keep both parts, and keep the wax block. The block stays with the laboratory. If a new marker test is needed later, it can often be done on the same block, without another endoscopy. When the first biopsy was very small, the tissue can run out, and a repeat endoscopy with more samples is then the fastest route.
The oldest and still the most useful way to sort stomach cancer is by how its cells are arranged. Most reports use these three words.
| Type | What the pathologist sees | What it means for treatment |
|---|---|---|
| Intestinal | The cancer cells form glands, like the lining of the bowel | Usually forms a clear lump or ulcer; the surgeon can often remove part of the stomach |
| Diffuse | Single cells scattered through the wall, with no glands | Spreads inside the wall beyond what the eye can see; needs wider margins and often removal of the whole stomach |
| Mixed | Both patterns in the same cancer | Usually treated like the diffuse type |
The type changes how much stomach the surgeon removes. A diffuse cancer creeps along the wall under a normal-looking lining, so the cut has to be further away from it.
Some reports use the newer WHO names instead. Tubular and papillary adenocarcinoma behave much like the intestinal type. Poorly cohesive carcinoma is the WHO name for the diffuse type. Mucinous adenocarcinoma means the cells make a lot of mucus.
Signet ring cells are a kind of diffuse cancer cell. Mucus pushes the nucleus to one side, so the cell looks like a signet ring under the microscope. When most of the cancer is made of these cells, the report calls it signet ring cell carcinoma.
Because of the risk of hidden spread, a signet ring cancer is usually checked with a short keyhole look inside the abdomen, called a staging laparoscopy, before any major operation.
The grade describes how far the cancer cells have moved away from normal stomach cells. Well differentiated cells still look a little like normal ones. Poorly differentiated cells look very different, and tend to grow faster.
A few other words appear often:
Some cancers of the stomach are not adenocarcinoma at all. Lymphoma, GIST and neuroendocrine tumours start in the stomach too, but they are different diseases with different treatment. The report names them clearly.
Markers are proteins or gene changes in the cancer cells. Each one tells the cancer team whether a particular medicine is likely to work. Four are now tested in every stomach adenocarcinoma.
| Marker | How the report shows it | What a positive result opens up |
|---|---|---|
| HER2 | A score of 0, 1+, 2+ or 3+; 2+ needs a second test called FISH or ISH | Trastuzumab and related medicines, added to chemotherapy |
| PD-L1 (CPS) | A number, the combined positive score | Immunotherapy added to chemotherapy |
| MSI or MMR | MSI-high, or MMR deficient (loss of one of four proteins) | Immunotherapy, which works well here; a check for a family syndrome |
| Claudin 18.2 | Positive or negative, by the share of cells that stain | Zolbetuximab, added to chemotherapy |
Larger laboratories may add a broad gene panel, mainly when the cancer has spread or come back. It can find rarer targets such as FGFR2b or an NTRK change.
HER2 is a growth signal on the surface of some cancer cells. It is found more often in the intestinal type and in cancers where the food pipe joins the stomach.
In a HER2-positive cancer that has spread, trastuzumab is given with chemotherapy from the start. Immunotherapy may be added as well. If the cancer grows again, a newer medicine, trastuzumab deruxtecan, is an option. HER2 testing is widely available in India and is not expensive.
Immunotherapy medicines, such as nivolumab and pembrolizumab, help the body’s own defence cells attack the cancer. PD-L1 and MSI are the two markers that predict whether they will help.
PD-L1 is reported as a number called the CPS. A higher number means immunotherapy is more likely to add benefit to chemotherapy in a cancer that has spread. The cut-off used depends on the medicine.
MSI-high, also written as MMR deficient, means the cancer has lost its ability to repair its own genes. Such cancers carry many changes that the defence cells can recognise. Immunotherapy often works well in them, whatever the PD-L1 number.
For an MSI-high cancer that can still be removed, the plan may change. Some of these cancers gain little from standard chemotherapy, and giving immunotherapy before the operation is being studied. This is a decision for a cancer team meeting, not a reason to delay.
Claudin 18.2 is a protein that holds stomach cells together. In many stomach cancers it is exposed on the cell surface. The medicine zolbetuximab locks onto it and marks the cancer cells for attack.
A cancer counts as Claudin 18.2 positive when most of its cells stain strongly. For such a cancer that has spread, and that is HER2 negative, zolbetuximab can be added to chemotherapy. The test is now reaching the larger laboratories in India.
FGFR2b and NTRK are rarer targets. They are looked for on a broad gene panel, usually after the first treatment for spread disease.
Two findings on a report can mean the cancer runs in the family. Either one is a reason to talk about a blood test for the patient, and checks for close relatives.
A genetic counsellor can explain the blood test and what a result would mean for brothers, sisters and children. A positive result changes how relatives are watched, often with regular endoscopy or colonoscopy.
A biopsy shows a few millimetres of lining. It cannot show how deep the cancer goes, or whether glands or the liver are involved.
It tells you the type of cancer under the microscope, such as intestinal or diffuse, its grade, and which markers it carries. It does not give the stage; that comes from scans and sometimes a staging laparoscopy.
It is a kind of diffuse stomach cancer in which mucus pushes each cell's nucleus to one side. It tends to spread to the lining of the abdomen, so a staging laparoscopy is usually done before a major operation.
It means the cancer cells carry extra HER2 growth signals, shown as a score of 3+ or a positive FISH test. If the cancer has spread, trastuzumab is added to chemotherapy.
The cancer has lost its gene repair system. Immunotherapy often works well in such cancers, and the patient may be offered a check for Lynch syndrome, which can run in families.
HER2, PD-L1 (CPS), MSI or MMR, and Claudin 18.2 should be tested in every stomach adenocarcinoma. They can usually be done on the same wax block without another endoscopy.
Not on its own. Whether surgery or chemotherapy comes first depends on the stage, which is worked out from the CT scan and other tests. The type on the report does change how much stomach is removed.
The full range of stomach cancer care is on the stomach cancer treatment page. For questions before you travel, call +91-63555-64601.
Shah’s Gastro, Cancer & Robotic Surgery Centre, Gota, Ahmedabad
Consultation, review of endoscopy, biopsy and CT reports, second opinions and follow-up.
Apollo Hospital, Bhat, Gandhinagar
Apollo Hospital International Limited, GIDC Bhat Industrial Estate, Bhat, Gandhinagar. Endoscopy and biopsy, CT and PET scans, chemotherapy, stomach cancer surgery and inpatient care.
Has a biopsy shown stomach cancer, and the report is full of words like signet ring, HER2 or MSI? The biopsy report, the endoscopy report and any scans can be sent ahead on WhatsApp, so the consultation starts with them already read. Your treatment is decided at the consultation, after examination. Call +91-63555-64601 Send your biopsy report before the visit
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