Breast cancer is characterized by the uncontrolled proliferation of breast cells, with a high incidence reported in 2020 to have affected over 2 million women. In recent years, the conventional methods of treating breast cancer have involved radiotherapy and chemotherapy. However, the emergence of CDK4/6 inhibitors has shown potential as a promising cancer therapy. Cyclin-dependent kinases (CDK) inhibitors are a class of molecules that impede the formation of an active kinase complex, thereby hindering its activity and consequently halting the progression of the cell cycle. It was discovered that they have a significant impact on impeding the progression of the cancer. This is evident with the Food and Drug Administration's approval of drugs such as palbociclib, ribociclib, and abemaciclib for hormone receptor-positive metastatic breast cancer in combination with specific endocrine therapies. In spite of enormous success in breast cancer treatment, certain obstacles have emerged, such as therapy resistance, side effects, and most of all, cardiotoxicity. Some of these drawbacks have been successfully overcome by dosage reduction, different combinations of the drugs, and the assessment of each patient's condition and suitability prior to treatment. Yet other drawbacks still require tenacious research, especially certain cases of cardiotoxicities. This article delves into the biological mechanisms of CDK4/6 in the cell cycle and cancer, as well as the clinical advantages and most common adverse events (AEs) associated with CDK4/6 inhibitors. The primary objective of this review is to provide a comprehensive analysis of cardiotoxic AEs and elucidate the underlying pathophysiological mechanisms responsible for the cardiotoxicity of CDK4/6 inhibitors.

中文翻译：

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CDK4/6 抑制剂：乳腺癌治疗的基础知识、优点和主要缺点，特别是心脏毒性 - 叙述性评论。

乳腺癌的特点是乳腺细胞不受控制的增殖，据报道，2020 年乳腺癌发病率很高，影响了超过 200 万女性。近年来，治疗乳腺癌的常规方法包括放疗和化疗。然而，CDK4/6 抑制剂的出现已显示出作为一种有前途的癌症治疗的潜力。细胞周期蛋白依赖性激酶 (CDK) 抑制剂是一类阻碍活性激酶复合物形成的分子，从而阻碍其活性，从而阻止细胞周期的进展。研究发现它们对阻止癌症的进展具有显着的作用。美国食品和药物管理局批准 palbociclib、ribociclib 和 abemaciclib 等药物与特定内分泌疗法联合治疗激素受体阳性转移性乳腺癌就证明了这一点。尽管乳腺癌治疗取得了巨大成功，但仍出现了一些障碍，例如治疗耐药性、副作用，最重要的是心脏毒性。其中一些缺点已通过减少剂量、药物的不同组合以及治疗前评估每个患者的病情和适合性而成功克服。然而其他缺点仍然需要顽强的研究，特别是某些心脏毒性病例。本文深入探讨了 CDK4/6 在细胞周期和癌症中的生物学机制，以及与 CDK4/6 抑制剂相关的临床优势和最常见的不良事件 (AE)。本综述的主要目的是对心脏毒性 AE 进行全面分析，并阐明导致 CDK4/6 抑制剂心脏毒性的潜在病理生理机制。