Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, which is characterized by the absence of estrogen receptor (ER) and progesterone receptor (PR) expression and the absence of human epidermal growth factor receptor 2 (HER2) expression/amplification. Conventional chemotherapy is the mainstay of systemic treatment for TNBC. However, lack of molecular targeted therapies and poor prognosis of TNBC patients have prompted a great effort to discover effective targets for improving the clinical outcomes. For now, poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi’s) and immune checkpoint inhibitors have been approved for the treatment of TNBC. Moreover, agents that target signal transduction, angiogenesis, epigenetic modifications, and cell cycle are under active preclinical or clinical investigations. In this review, we highlight the current major developments in targeted therapies of TNBC, with some descriptions about their (dis)advantages and future perspectives.

Adenoid cystic carcinoma of the salivary gland (SACC) is a rare malignant tumors of the head and neck region, but it is one of the most common malignant tumors that are prone to perineural invasion (PNI) of the head and neck. The prognosis of patients with SACC is strongly associated with the presence of perineural spread (PNS). Although many contributing factors have been reported, the mechanisms underlying the preferential destruction of the blood-nerve barrier (BNB) by tumors and the infiltration of the tumor microenvironment by nerve fibers in SACC, have received little research attention. This review summarizes the current knowledge concerning the characteristics of SACC in relation to the PNI, and then highlights the interplay between components of the tumor microenvironment and perineural niche, as well as their contributions to the PNI. Finally, we provide new insights into the possible mechanisms underlying the pathogenesis of PNI, with particular emphasis on the role of extracellular vesicles that may serve as an attractive entry point in future studies.

Extracellular vesicles (EVs, including exosomes) are a group of heterogeneous nanometer‐sized vesicles that are released by all types of cells and serve as functional mediators of cell‐to‐cell communication. This ability is primarily due to their capacity to package and transport various proteins, lipids, and nucleic acids—namely DNA and messenger RNA (mRNA), but also microRNAs (miRNAs) and long non‐coding RNAs (lncRNAs). These contents can influence the function and fate of both recipient and donor cells. More and more studies have shown that EVs are involved in every phase of cancer development, mediating bidirectional cross talk between cancer cells and their tissue microenvironment. More specifically, EVs can promote tumor progression by modifying vesicular contents and establishing a distant premetastatic niche with molecules that favor cancer cell proliferation, migration, invasion, metastasis, angiogenesis, and even drug resistance. Given that the packaging of these molecules is known to be tissue‐specific, EVs can not only serve as novel prognostic and diagnostic markers but also be used as potential therapeutic targets and vehicles for drug delivery. The present review discusses the current understanding of the multifaceted roles of EVs in the progression of oral and salivary gland cancers, as well as their potential use in clinical applications.