Samples taken during biopsies, blood tests or other tests are sent to a pathology laboratory. A pathologist, a doctor who uses laboratory tests to diagnose diseases such as cancer, will look at the samples and may perform other special tests to help better classify the cancer. These tests can also help you choose certain drugs that may work better for your cancer. It's called timeprecision or personalized medicinebecause it is accurate (or specific) to the characteristics of your cancer.
The results of these tests are detailed in a pathology report, which is usually available within a week or two. If you have any questions about your pathology results or diagnostic tests, talk to your doctor. If necessary, you can get a second opinion on the pathology report by sending tissue samples to a pathologist in another laboratory.
Tests for the presence of certain proteins on cancer cells
Laboratory tests may also be done to look for certain proteins in cancer cells.
Hormone Receptor Proteins:All breast cancers are screened for hormone receptors (proteins). Specifically, cancer is screened for the estrogen receptor (ER) and the progesterone receptor (PR). read more onBreast cancer hormone receptor status.
HER2 protein:All invasive breast cancers are tested for the presence of the HER2 protein to see if too much of it is being produced. If it is not clear how much HER2 protein is present, breast cancer cells can then be molecularly tested for gene changes to see how many copies of the HER2 gene are being made. For more information about the HER2 gene and protein, seeBreast cancer HER2 status.
PD-L1 protein:People with advanced or metastatic triple-negative breast cancer can have the cancerous tissue examined for cancerPD-L1a protein that can show whether a cancer is more likely to respond to certain treatmentsimmunotherapymedication along with chemotherapy.
Molecular testing of gene changes
In some cases, doctors can test for specific gene changes in breast cancer cells, which can mean certain thingstargeted substancesor immunotherapy drugs can help treat cancer.
These molecular tests can be performed on tissue taken during a breast cancer biopsy or surgery. If the biopsy sample is too small and all molecular tests cannot be performed, the test can also be performed on blood taken from a vein, just like a regular blood draw. This blood contains DNA from dead cancer cells (calledcirculating tumor DNA, LubctDNA). Obtaining tumor DNA by drawing blood is sometimes called a "liquid biopsy."and may have advantages over standard needle biopsy, which may carry risks.
Some genes that can be tested for include:
- BRCA1IBRCA2mutations:For women with HER2-negative advanced breast cancer, your doctor may test you (instead of your cancer cells) forinherited BRCA1 or BRCA2 mutation(gene change). If you have one of these gene changes, treatment with targeted drugs, olaparib (Lynparza) or talazoparib (Talzenna), may be an option.
- PIK3CAgenmutation:Cancer cells that have a form of PI3K protein can help them grow. This protein comes from the abnormalPIK3CAgenetic modification. If the breast cancer is hormone receptor-positive and HER2-negative, and the breast cancer cells show this specific gene change, the target drug calpelisib (Piqray) along withhormonal substancefulvestrant (Faslodex) can be used.
- ESR1gene mutations:TheESR1the gene contains the cell's instructions for the estrogen receptor (ER) protein. Mutations in this gene can make breast cancer less susceptible to some forms of hormone therapy. However, in advanced breast cancer, the hormone elacestrant (Orserdu) can be useful if the cancer cells haveESR1mutation. This gene change can be tested in a blood test.
- Testy MSI and MMR:Breast cancer cells can be tested to see if they show high levels of gene changes called microsatellite instability (MSI). Tests can also be done to see if cancer cells have changes in any of the mismatch repair (MMR) genes (MLH1,MSH2,MSH6, iPMS2).The breast cancer cells they havehigh level of microsatellite instability (MSI-H)thea defect in the mismatch repair gene (dMMR)can be treated with immunotherapy drugs, pembrolizumab (Keytruda) or dostarlizumab (Jemperli).
- Tumor mutationsbelastning (TMB):TMB is a measure of the number of gene mutations (changes) inside cancer cells. Breast cancer cells that have more gene mutations (high TMB) may be more likely to be recognized as abnormal and attacked by the body's immune system. If your breast cancer tissue is tested and found to have ithigh TMB (TMB-H)treatment with pembrolizumab (Keytruda) may be an option.
- NTRKfusion genes:Some breast cancer cells may have changes in one of the cellsNTRKannoyances. These gene changes can sometimes lead to cancer growth. Larotrectinib (Vitrakvi) and dentrectinib (Rozlytrek) are drugs that target proteins made by abnormalNTRKgenes and may be options for people with advanced breast cancer.
Blood tests are not used to diagnose breast cancer, but they can help understand a person's overall health. For example, they can be used to determine whether a person is healthy enough to undergo surgery or certain types of chemotherapy.
INcomplete blood count (CBC)checks whether there are normal numbers of different types of blood cells in the blood. For example, it can show whether you are anemic (low number of red blood cells), may have bleeding problems (low number of platelets) or have an increased risk of infection (low number of white blood cells). This test may be repeated regularly during treatment because many anticancer drugs can affect the hematopoietic cells in the bone marrow.
Blood chemistry testsit can help tell if some organs, such as the liver or kidneys, are also not working properly. For example, if cancer has spread to the bones, it can result in higher than normal levels of calcium and alkaline phosphatase. If breast cancer has spread to the liver, it can sometimes cause high levels of liver function tests such as aspartate aminotransferase (AST) or alanine aminotransferase (ALT). Breast cancer does not spread to the kidneys, but if a blood test shows that the kidneys are not working well, some chemotherapy drugs such as cisplatin may not be used.
Breast cancer cells sometimes produce substances calledTumor markersthat can be found in the blood. For breast cancer that has spread to other organs, tumor markers that can be checked include carcinoembryonic antigen (CEA), cancer antigen 15-3 (CA 15-3), and cancer antigen 27-29 (CA 27-29). Blood tests for these tumor markers are not used by themselves to diagnose or track breast cancer
American Cancer Society medical content and editorial team Our team consists of oncology doctors and nurses with deep knowledge of oncology treatment as well as journalists, editors and translators with extensive experience in writing medical texts.
American Cancer Society medical content and editorial team
Our team consists of oncology doctors and nurses with deep knowledge of oncology treatment as well as journalists, editors and translators with extensive experience in writing medical texts.
Burstein HJ, Somerfield MR, Barton DL et al. Hormone therapy and targeted therapy for the treatment of hormone receptor-positive and human epidermal growth factor receptor 2 metastatic breast cancer: an update of the ASCO guidelines [published online ahead of print July 29, 2021].J Clin Oncol. 2021;JCO2101392. doi:10.1200/JCO.21.01392. National Comprehensive Cancer Network (NCCN). Oncology Practice Guidelines: Breast Cancer. Version 8.2021 - September 13, 2021. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf on September 14, 2021. Van Poznak C, Somerfield MR, Bast RC et al. Use of biomarkers to inform systemic therapy decisions for women with metastatic breast cancer: American Society of Clinical Oncology Clinical Practice Guidelines.J Clin Oncol. 2015;33(24):2695-2704. doi:10.1200/JCO.2015.61.1459.
Burstein HJ, Somerfield MR, Barton DL et al. Hormone therapy and targeted therapy for the treatment of hormone receptor-positive and human epidermal growth factor receptor 2 metastatic breast cancer: an update of the ASCO guidelines [published online ahead of print July 29, 2021].J Clin Oncol. 2021;JCO2101392. doi:10.1200/JCO.21.01392.
National Comprehensive Cancer Network (NCCN). Oncology Practice Guidelines: Breast Cancer. Version 8.2021 - September 13, 2021. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf on September 14, 2021.
Van Poznak C, Somerfield MR, Bast RC et al. Use of biomarkers to inform systemic therapy decisions for women with metastatic breast cancer: American Society of Clinical Oncology Clinical Practice Guidelines.J Clin Oncol. 2015;33(24):2695-2704. doi:10.1200/JCO.2015.61.1459.
Last seen:31 January 2023
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HER2 protein: All invasive breast cancers are tested for the HER2 protein to see if too much is being made. If it is not clear how much HER2 protein is present, the breast cancer cells might then undergo molecular testing for gene changes to see how many copies of the HER2 gene are being made.Can breast cancer cause high protein in blood? ›
The mean values of the protein concentration in the serum of breast cancer patients were significantly higher than those in healthy individuals with a statistical significance (P<0.05), whereas the mean levels of the saliva protein concentrations in the breast cancer group were lower than the mean level for the healthy ...Can breast cancer show up on blood work? ›
The study demonstrated that the blood test can determine whether a patient has breast cancer in the early stages. A special blood test, called a liquid biopsy, could determine whether a patient has breast cancer in its early stages and if that cancer is unlikely to return.What is the blood test for breast cancer gene? ›
A BRCA gene test uses a sample of your blood, saliva (spit), or cells from inside of your cheek to look for changes in your BRCA1 and BRCA2 genes that may increase your risk of cancer. Changes in your genes are called gene variants or mutations. Not all gene variants are harmful.What proteins in blood indicate cancer? ›
A CA-125 test measures the amount of the cancer antigen 125 (CA-125) in a person's blood. CA-125 is a protein that is a biomarker or tumor marker. The protein is found in higher concentration in cancer cells, particularly ovarian cancer cells.What bloodwork would be elevated with breast cancer? ›
For example, if cancer has spread to the bones, it might cause higher than normal levels of calcium and alkaline phosphatase. If breast cancer spreads to the liver, it can sometimes cause high levels of liver function tests, such as aspartate aminotransferase (AST) or alanine aminotransferase (ALT).What protein is associated with breast cancer? ›
For many years, scientists have known that mutations in the genes coding for the proteins BRCA1 and BRCA2 increase risk of breast and ovarian cancer by 30% to 70% and account for half of all hereditary cases of the diseases.Would a CBC show signs of breast cancer? ›
Aside from leukemia, most cancers cannot be detected in routine blood work, such as a CBC test. However, specific blood tests are designed to identify tumor markers, which are chemicals and proteins that may be found in the blood in higher quantities than normal when cancer is present.Does breast cancer affect your white blood cell count? ›
The types of white blood cells in the bloodstream may shift in the years leading up to a breast cancer diagnosis, according to a new study. Shifts in the populations of white blood cells in a woman's bloodstream may signal a later diagnosis of breast cancer, according to a study by NIEHS researchers, published Jan.What does it mean if you test positive for the breast cancer gene? ›
A positive test result indicates that a person has inherited a known harmful variant in BRCA1 or BRCA2 (these are typically called “pathogenic” or “likely pathogenic” variants on laboratory test reports) and has an increased risk of developing certain cancers.
The BRCA gene test is a blood test that's done to determine if you have changes (mutations) in your DNA that increase the risk of breast cancer. Mutations in either breast cancer gene — BRCA1 or BRCA2 — significantly increase the risk of: Breast cancer.Is breast cancer inherited from mother or father? ›
Having a family history of breast cancer
Having a first-degree relative (mother, sister, or daughter) with breast cancer almost doubles a woman's risk. Having 2 first-degree relatives increases her risk by about 3-fold. Women with a father or brother who has had breast cancer also have a higher risk of breast cancer.
A high total protein level could indicate dehydration or a certain type of cancer, such as multiple myeloma, that causes protein to accumulate abnormally. If the result of a total protein test is abnormal, further tests will be needed to identify which proteins are too high or too low.What shows cancer in CBC? ›
Higher-than-normal numbers of lymphocytes or monocytes can indicate the possibility of certain types of cancer. Some cancers and their treatment may cause low numbers of neutrophils, a condition called neutropenia. Neutropenia can increase your chance of a bacterial infection.How I found out I had inflammatory breast cancer? ›
The symptoms of inflammatory breast cancer vary from patient to patient. However, it may be asymptomatic in some cases. Breast swelling, redness, and irritated itching are some common symptoms reported by many people with inflammatory breast cancer.Can cancer cause high protein levels in blood? ›
Many things may cause high blood protein levels, from dehydration to infections to certain blood cancers.Can high protein indicate cancer? ›
Elevated CRP levels (> 10 μg/ml) are associated with active, advanced cancer disease.Does cancer show up in routine blood work? ›
Aside from leukemia, most cancers cannot be detected in routine blood work, such as a CBC test. However, specific blood tests are designed to identify tumor markers, which are chemicals and proteins that may be found in the blood in higher quantities than normal when cancer is present.