癌症免疫疗法，听起来像是一场高科技的医学战争，但实际上，它更像是一场“猫鼠游戏”，在这场游戏中，癌细胞是狡猾的老鼠，而我们的免疫系统则是那只时而机敏、时而迟钝的猫，免疫疗法的目标，就是让这只猫重新变得机灵起来，抓住那些四处逃窜的老鼠，在这场“猫鼠游戏”中，我们到底需要检测什么呢？别急,让我用幽默的文笔为你揭开这场医学大戏的帷幕。
检测免疫细胞的“战斗力”
免疫疗法的核心是激活我们的免疫系统，让它重新识别并攻击癌细胞，检测的第一步就是看看我们的免疫细胞是否“战斗力在线”，这些免疫细胞包括T细胞、NK细胞（自然杀伤细胞）和巨噬细胞等，它们就像是免疫系统的“特种部队”,负责消灭入侵者。
通过血液检测，我们可以评估这些免疫细胞的数量和活性，如果发现T细胞“懒洋洋”地躺在那里，或者NK细胞“打瞌睡”，那就说明免疫系统需要“唤醒”了，免疫疗法的任务之一，就是通过药物（如PD-1抑制剂或CTLA-4抑制剂）让这些细胞重新“振作”起来,投入战斗。
检测癌细胞的“伪装术”
癌细胞之所以难对付，很大程度上是因为它们擅长“伪装”，它们会通过表达某些蛋白质（如PD-L1）来“欺骗”免疫细胞，让免疫细胞误以为它们是“自己人”，从而逃避免疫系统的攻击，这就好比老鼠穿上了一件隐形斗篷,猫怎么也找不到它。
检测癌细胞的“伪装术”是免疫疗法中的关键一步，通过活检或血液检测，我们可以分析癌细胞是否表达PD-L1等蛋白质，如果发现癌细胞“伪装”得特别好，医生可能会选择使用PD-1或PD-L1抑制剂来“撕掉”它们的伪装,让免疫细胞重新识别并攻击它们。
检测肿瘤突变负荷（TMB）
肿瘤突变负荷（TMB）听起来像是一个复杂的术语，但其实它很简单：它指的是肿瘤细胞中基因突变的数量，突变越多，癌细胞产生的异常蛋白质就越多，这些异常蛋白质就像是癌细胞的“身份证”,更容易被免疫系统识别。
通过基因测序，我们可以计算肿瘤的TMB，高TMB的肿瘤通常对免疫疗法反应更好，因为它们的“身份证”更明显，免疫细胞更容易找到并攻击它们，检测TMB就像是给免疫系统提供了一张“通缉令”，上面详细列出了癌细胞的“特征”。
检测微卫星不稳定性（MSI）
微卫星不稳定性（MSI）是另一个重要的检测指标，微卫星是DNA中的一小段重复序列，正常情况下它们是稳定的，但在某些肿瘤中，这些序列会变得不稳定，导致大量基因突变，高MSI的肿瘤通常对免疫疗法反应良好，因为它们会产生大量异常蛋白质,更容易被免疫系统识别。
检测MSI通常通过基因测序完成，如果发现肿瘤是高MSI，医生可能会优先考虑免疫疗法，因为这类肿瘤的“漏洞”更多,免疫细胞更容易找到并消灭它们。
检测免疫相关副作用
免疫疗法虽然强大，但它也可能引发一些副作用，这是因为激活的免疫细胞不仅会攻击癌细胞，还可能误伤正常组织，这种副作用被称为“免疫相关不良事件”（irAEs），可能影响皮肤、肠道、肝脏甚至肺部。
在免疫疗法过程中，医生会定期检测患者的肝功能、肾功能、血常规等指标，以及观察是否有皮疹、腹泻、呼吸困难等症状，如果发现副作用，医生会及时调整治疗方案,确保患者的安全。
检测疗效：肿瘤缩小了吗？
免疫疗法的终极目标是缩小甚至消灭肿瘤，医生会通过影像学检查（如CT、MRI或PET-CT）来评估肿瘤的大小和数量，如果肿瘤明显缩小或消失，那就说明免疫疗法奏效了，如果肿瘤没有变化甚至增大,医生可能需要调整治疗方案。
在这场与癌细胞的“猫鼠游戏”中，免疫疗法检测的内容涵盖了免疫细胞的战斗力、癌细胞的伪装术、肿瘤的突变负荷和微卫星不稳定性等多个方面，通过这些检测，医生可以制定个性化的治疗方案，帮助患者在这场“战争”中取得胜利。
免疫疗法并不是万能的，它也有局限性和副作用，但无论如何，它为我们提供了一种全新的抗癌武器，希望未来的医学研究能让这场“猫鼠游戏”变得更加公平，最终让“猫”彻底战胜“老鼠”！
English Translation:
Title: What Does Cancer Immunotherapy Test? – A "Cat and Mouse" Game with Cancer Cells
Cancer immunotherapy sounds like a high-tech medical war, but in reality, it’s more like a "cat and mouse" game. In this game, cancer cells are the cunning mice, and our immune system is the cat that is sometimes sharp and sometimes sluggish. The goal of immunotherapy is to make this cat sharp again, catching those elusive mice. So, in this "cat and mouse" game, what exactly do we need to test? Don’t worry, let me use a humorous writing style to unveil the curtain of this medical drama.
Testing the "Combat Power" of Immune Cells
First, the core of immunotherapy is to activate our immune system, allowing it to recognize and attack cancer cells again. Therefore, the first step in testing is to see if our immune cells are "combat-ready." These immune cells include T cells, NK cells (natural killer cells), and macrophages, among others. They are like the "special forces" of the immune system, responsible for eliminating invaders.
Through blood tests, we can assess the number and activity of these immune cells. If T cells are found "lazing around" or NK cells are "dozing off," it means the immune system needs to be "awakened." One of the tasks of immunotherapy is to use drugs (such as PD-1 inhibitors or CTLA-4 inhibitors) to "revive" these cells and get them back into the fight.
Testing the "Disguise" of Cancer Cells
The reason cancer cells are so difficult to deal with is largely because they are good at "disguising" themselves. They express certain proteins (such as PD-L1) to "trick" immune cells into thinking they are "one of us," thereby evading the immune system’s attack. It’s like a mouse wearing an invisibility cloak, making it impossible for the cat to find it.
Therefore, testing the "disguise" of cancer cells is a crucial step in immunotherapy. Through biopsies or blood tests, we can analyze whether cancer cells express proteins like PD-L1. If it’s found that cancer cells are particularly good at "disguising," doctors may choose to use PD-1 or PD-L1 inhibitors to "rip off" their disguise, allowing immune cells to recognize and attack them again.
Testing Tumor Mutational Burden (TMB)
Tumor Mutational Burden (TMB) sounds like a complex term, but it’s actually quite simple: it refers to the number of gene mutations in tumor cells. The more mutations there are, the more abnormal proteins the cancer cells produce. These abnormal proteins are like the "ID cards" of cancer cells, making them easier for the immune system to recognize.
Through gene sequencing, we can calculate the TMB of a tumor. Tumors with high TMB usually respond better to immunotherapy because their "ID cards" are more obvious, making it easier for immune cells to find and attack them. So, testing TMB is like providing the immune system with a "wanted poster," detailing the "features" of cancer cells.
Testing Microsatellite Instability (MSI)
Microsatellite Instability (MSI) is another important testing indicator. Microsatellites are small repetitive sequences in DNA that are normally stable. However, in some tumors, these sequences become unstable, leading to a large number of gene mutations. Tumors with high MSI usually respond well to immunotherapy because they produce a large number of abnormal proteins, making them easier for the immune system to recognize.
Testing for MSI is usually done through gene sequencing. If a tumor is found to have high MSI, doctors may prioritize immunotherapy because such tumors have more "vulnerabilities," making it easier for immune cells to find and eliminate them.
Testing Immune-Related Side Effects
Although immunotherapy is powerful, it can also cause some side effects. This is because activated immune cells not only attack cancer cells but may also mistakenly harm normal tissues. This type of side effect is called "immune-related adverse events" (irAEs) and can affect the skin, intestines, liver, and even lungs.
Therefore, during immunotherapy, doctors will regularly test patients’ liver function, kidney function, blood counts, and other indicators, as well as observe for symptoms like rashes, diarrhea, or difficulty breathing. If side effects are detected, doctors will adjust the treatment plan in time to ensure the patient’s safety.
Testing Efficacy: Has the Tumor Shrunk?
Finally, the ultimate goal of immunotherapy is to shrink or even eliminate the tumor. Therefore, doctors will use imaging tests (such as CT, MRI, or PET-CT) to assess the size and number of tumors. If the tumor significantly shrinks or disappears, it means immunotherapy is working. If the tumor remains unchanged or even grows, doctors may need to adjust the treatment plan.
Conclusion
In this "cat and mouse" game with cancer cells, immunotherapy testing covers multiple aspects, including the combat power of immune cells, the disguise of cancer cells, the tumor’s mutational burden, and microsatellite instability. Through these tests, doctors can develop personalized treatment plans to help patients win this "war."
Of course, immunotherapy is not a cure-all; it has limitations and side effects. But regardless, it provides us with a new weapon against cancer. Hopefully, future medical research will make this "cat and mouse" game more fair, ultimately allowing the "cat" to completely defeat the "mouse"!
