ABSTRACT
Over the last decade, treatment paradigms for breast cancer have undergone a renaissance, particularly in hormone-receptor-positive/HER2-negative breast cancer. These revolutionary therapies are based on the selective targeting of aberrancies within the cell cycle. This shift towards targeted therapies has also changed the landscape of disease monitoring. In this article, we will review the fundamentals of cell cycle progression in the context of the new cyclin-dependent kinase inhibitors. In addition to discussing the currently approved cyclin-dependent kinase inhibitors for breast cancer, we will explore the ongoing development and search for predictive biomarkers and modalities to monitor treatment.
Subject(s)
Breast Neoplasms , Humans , Female , Breast Neoplasms/drug therapy , Breast Neoplasms/metabolism , Cyclin-Dependent Kinase 4 , Cyclin-Dependent Kinase 6 , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Biomarkers , Receptor, ErbB-2/metabolismABSTRACT
Merkel cell carcinoma (MCC) is a rare neuroendocrine dermal malignancy seen in elderly light-skinned individuals, associated with immunosuppression and Merkel cell polyomavirus infection. As a neuroendocrine tumor, the recurrence and metastasis of MCC can be evaluated using positron emission tomography-computed tomography (PET-CT) with the Gallium-68-DOTATATE (Ga-68-DOTATATE) radiotracer, which has demonstrated increased sensitivity to neuroendocrine metastases when compared to F-18 fluorodeoxyglucose (FDG). Here, we present the case of a patient with known metastatic MCC with a new, abnormal focus of increased radiotracer activity in the thoracic spine on Ga-68-DOTATATE PET-CT suspected to represent a metastatic lesion. Further evaluation with MRI revealed a benign vertebral hemangioma, highlighting the limitations of this radiotracer in the setting of benign spinal lesions. Multimodality imaging findings of metastatic MCC and potential pitfalls of Ga-68-DOTATATE PET-CT staging are discussed.
