Recently, some patients often ask me this question in clinical work: “Is a high tumor marker a cancer? How to correctly understand tumor markers? And how to correctly understand what does an increase in tumor markers mean? Today, we will do a little popularization to unveil the mystery of tumor markers! Tumor marker is literally a sign of tumor disease, but in fact, not all tumor diseases should show increased tumor marker. AFP, a tumor marker for primary liver cancer, can be detected in embryos, infants, pregnant women or adults or can be detected at higher than normal values. It is obvious that if elevated AFP is detected in infants, pregnant women or people with hepatitis who have no disease or benign disease, we cannot diagnose them as having cancer. Strictly speaking, specific tumor markers are those that must be present or detected in patients with tumors, while those without tumors must not be detected, which is the real specific tumor markers. Then how should high tumor markers be understood? Let’s look at the following situations. High single tumor marker: Strictly speaking, high single tumor marker cannot diagnose any kind of tumor, because tumor markers are divided into many kinds, such as frequently detected glycoproteins (CA199, CA242, CA125, etc.), proteins (AFP, CEA, TPA, etc.), enzymes (ALP, LDH, etc.), hormones (ACTH, HCG, etc.), polyamines (5-HT, etc.). These markers are present in many organs and tissues, so it is not possible to say which organ has a tumor by the increase of a single marker. At this time, it does not mean anything, but the alarm bell is ringing and we should go further to find out whether there are changes in other tests, so usually we need to rely on ultrasound, CT or MRI to further clarify whether there is a tumor or not, and even pathological examination or nucleic acid amplification test is needed to prove it. If other examinations do not prove the existence of tumor, can we celebrate it? Therefore, we advocate that people with high single tumor markers and family history of tumor-related diseases should be followed up and tested. For people with no family history of tumor, we generally need to follow up the test for the first 4 weeks, 8 weeks, 3 months, 6 months, and partly for 1 year to observe whether the marker is consistently elevated or not, and for people with family history of tumor, we need to observe at least 1-3 years. Multiple tumor marker elevation: If multiple tumor markers are elevated, we should be very careful about this. We must go to a good hospital to do a systematic test to clarify whether there is really a tumor disease, and we should do a comprehensive test for the tumor diseases with high prevalence in the family. Elevated serum tumor markers: In most cases, the tumor markers we detect come from the results of blood tests. If the tumor markers are elevated, we still need to see whether it is a single or multiple tumor markers that are elevated to decide what to do further! Pathological tumor marker increase: If the tumor marker result comes from human tissue, which is what we call pathological immunohistochemical examination, the high result can basically determine the tumor diagnosis, after all, at the current medical level, pathological examination is the gold standard for diagnosing diseases. For patients with clear tumor diagnosis, they should also check tumor markers regularly, because tumor markers from high level before treatment to decrease after treatment is the clinical standard for effective tumor treatment, if it doesn’t decrease or reverse high, it should be considered that tumor treatment is ineffective, recurrence or metastasis. Which people should be tested for tumor markers In China, 6 people are diagnosed with cancer every minute. The rate of death due to cancer is 12.94%. About 1 in 5 people may develop cancer and about 1 in 8 people may die from cancer! The mortality rate of men is higher than that of women, and the incidence rate of people over 50 years old accounts for more than 80% of the total incidence, while the incidence rate of cancer over 60 years old exceeds 1% and reaches the peak at 80 years old. Those who have a family history of tumor or in areas with a high incidence of certain tumors should start to check tumor markers 5-10 years in advance, and 3-5 years in advance to start supplementary imaging examination; 3. Here we also suggest that tumor markers should also be paid attention to those people who live high stress life, long-term celibacy and low family life expectancy. Finally, we hope that we can understand tumor markers correctly and detect and treat diseases early.