Apoptosis is an evolutionarily conserved sequential process of cell death to maintain a homeostatic balance between cell formation and cell death. It is a vital process for normal eukaryotic development as it contributes to the renewal of cells and tissues. Further, it plays a crucial role in the elimination of unnecessary cells through phagocytosis and prevents undesirable immune responses. Apoptosis is regulated by a complex signaling mechanism, which is driven by interactions among several protein families such as caspases, inhibitors of apoptosis proteins, B-cell lymphoma 2 (BCL-2) family proteins, and several other proteases such as perforins and granzyme. The signaling pathway consists of both pro-apoptotic and pro-survival members, which stabilize the selection of cellular survival or death. However, any aberration in this pathway can lead to abnormal cell proliferation, ultimately leading to the development of cancer, autoimmune disorders, etc. This review aims to elaborate on apoptotic signaling pathways and mechanisms, interacting members involved in signaling, and how apoptosis is associated with carcinogenesis, along with insights into targeting apoptosis for disease resolution.

Liquid biopsy offers dynamic and noninvasive analysis of cellular biomarkers, thereby presenting enormous potential for early detection of cancer, cancer staging, prediction of relapse, real-time examination of therapeutic efficacy, perception of therapeutic targets, and understanding the resistance mechanisms. Nanotechnology has emerged as a novel tool to widen the application horizon of liquid biopsy. Several nanomaterials, nanodevices, nanostructures, and nanosensors have been explored for improved application of liquid biopsy for biomarker detection. The circulating tumor cells (CTCs), circulating tumor proteins (CTP), miRNA and extracellular vesicles (EVs) are some of the important biomarkers for detection by liquid biopsy in bodily fluids. Herein, we have discussed the state of the art and beyond in advances in nanotechnology and in increasing the specificity, sensitivity, and purity with which we detect liquid biopsy biomarkers. The opportunities and prospects of these advanced innovative nanomaterials and technologies in clinical applications are explored. Furthermore, various isolation and biosensing strategies for visualization and signal amplification using nanomaterials are summarized. The utilization of nanotechnology-based liquid biopsy may provide greater insights for improved treatment, diagnosis, and prognosis of cancer.