早期癌症筛查是预防其发展和改善疾病预后的关键。一种准确有效的癌症筛查方法是使用高灵敏度生物传感器来检测光学、化学或磁性标记的癌症生物标志物。在广泛的生物传感器中，基于巨磁电阻（GMR）的设备具有高灵敏度、低背景噪声、可靠性和低成本的特点。借助最先进的微纳加工技术，数十至数百个独立工作的GMR生物传感器可集成到指甲大小的芯片上，用于多个癌症生物标志物的同时检测（即多重对比分析）。同时，GMR芯片的微型化使其能够集成到点对点（POC）设备中。在本综述中，我们首先介绍了三种类型的GMR生物传感器，包括其结构和物理性质，然后讨论了这些传感器的制造技术。为了实现目标癌症生物标志物的检测，GMR生物传感器表面需要进行生物修饰。因此，我们还回顾了常用的表面功能化方法。GMR基于生物传感器在癌症检测中的稳定性由全球多个研究团队展示，并对一些代表性实例进行了综述。在本综述的最后，我们对GMR生物传感器平台的挑战和未来发展前景进行了评述。考虑到其所有的优势和机会，可以预见GMR生物传感器平台将在不久的将来从一个有前景的候选者转变为癌症筛查的强大产品。

Early-stage screening of cancer is critical in preventing its development and therefore can improve the prognosis of the disease. One accurate and effective method of cancer screening is using high sensitivity biosensors to detect optically, chemically, or magnetically labeled cancer biomarkers. Among a wide range of biosensors, giant magnetoresistance (GMR) based devices offer high sensitivity, low background noise, robustness, and low cost. With state-of-the-art micro- and nanofabrication techniques, tens to hundreds of independently working GMR biosensors can be integrated into fingernail-sized chips for the simultaneous detection of multiple cancer biomarkers (i.e., multiplexed assay). Meanwhile, the miniaturization of GMR chips makes them able to be integrated into point-of-care (POC) devices. In this review, we first introduce three types of GMR biosensors in terms of their structures and physics, followed by a discussion on fabrication techniques for those sensors. In order to achieve target cancer biomarker detection, the GMR biosensor surface needs to be subjected to biological decoration. Thus, commonly used methods for surface functionalization are also reviewed. The robustness of GMR-based biosensors in cancer detection has been demonstrated by multiple research groups worldwide and we review some representative examples. At the end of this review, the challenges and future development prospects of GMR biosensor platforms are commented on. With all their benefits and opportunities, it can be foreseen that GMR biosensor platforms will transition from a promising candidate to a robust product for cancer screening in the near future.