Periodontitis is a chronic inflammatory disease. The heterotopic colonization of periodontal pathogens results in the development of several systemic diseases. Porphyromonas gingivalis (P. gingivalis), a key pathogen for periodontitis, has been linked to the development of various cancers, such as oral squamous cell carcinoma (OSCC), lung cancer, esophageal cancer, pancreatic cancer, colorectal cancer, cervical cancer, and prostate cancer. P. gingivalis promote the progression of tumor through various mechanisms, P. gingivalis regulates proteins targeting cell cycle and apoptosis to promote proliferation of tumor cells directly, enhances tumor stemness by upregulating the expression of cluster of differentiation 44 (CD44) and cluster of differentiation 133 (CD133), activates inflammasome and p38/c-Jun N-terminal kinase 1(JNK) pathways, regulates tumor-associated neutrophil (TAN) polarization to remodel the tumor microenvironment, regulates epithelial-mesenchymal transition (EMT) to promote tumor metastasis, remodel macrophage function to evade host immune response, and regulates multi-communicating with symbiotic bacteria. In addition, P. gingivalis accelerates the progression of esophageal cancer, pancreatic cancer, colorectal cancer, and prostate cancer by promoting cell proliferation, inhibiting apoptosis, inducing chronic inflammation, and escaping immunity. However, the oral microbiome is a complex system, whether the interactions between oral bacteria affect tumor progression needs to be further investigated.

Oral cancer is one of the most common malignancies in the head and neck regions. few patients benefit from current clinical therapy. Zinc finger proteins (ZNFs) are one of the largest transcription factor family proteins in the human genome. ZNFs bind to DNA, RNA, and proteins through their unique three-dimensional structure created by zinc ions to regulate gene transcription, RNA packaging, and protein folding. In recent years, the number of studies focused on the functional mechanism of ZNFs in regulating the progression of oral cancer has been increasing, with focuses on: ① ZNF677, ZNF460, ZNF154, ZNF132, ZNF281, Kaiso, and ZNF582, which regulate the invasion and metastasis of tumor cells; ② ZNF750 and PEST-containing nuclear protein (PCNP), which regulate the cell cycle; ③ ZNFs, which are involved in forming the tumor immune microenvironment, such as ZNF71 and myeloid zinc finger 1 (MZF1). For example, methylation modification modulates the reduction of ZNF677 in oral cancer and reduces the proliferation, migration, and invasion of oral cancer cells by inhibiting the protein kinase B/forkhead box O3a (AKT/FOXO3a) pathway; and ZNF460 promotes the proliferation, migration, and invasion of oral cancer cells by regulating microRNA-320a/alpha thalassemia/mental retardation, X-linked (ATRX) axis. In addition, ZNF750 inhibits the growth and metastasis of oral cancer by suppressing cell cycle transcription factor activity. Further, ZNF71 promotes the progression of oral cancer by reducing the infiltration of tumor immune cells. In this review, we will summarize the molecular mechanism, regulatory meshwork, and pro-tumor and anti-tumor roles of ZNFs in the pathogenesis of oral cancer. Our study may provide a new strategy for the diagnosis and treatment of oral cancer.

Oral squamous cell carcinoma (OSCC), the most common type of head and neck malignancy, has a poor prognosis owing to its high invasiveness and high rate of cervical lymph node metastasis. The tumor microenvironment (TME) is a complex microenvironment that is essential for tumor cell survival. Tumor-associated immune cell (TAIC), the main stromal cell of TME, regulates the proliferation, invasion, epithelial-mesenchymal transformation (EMT), and anti-tumor immunity of OSCC. M2-tumor-associated macrophages (TAMs) promote the invasion and metastasis of OSCC through the macrophage migration inhibitory factor/NOD-like receptor family pyrin domain containing 3/interleukin (IL)-1β axis, while N2-tumor-associated neutrophils (TANs) regulate the proliferation and EMT of OSCC through the Janus kinase 2/signal transducer and activator of transcription 3 pathway. Meanwhile, myeloid-derived suppressor cells (MDSCs) accelerate the progression of OSCC by secreting IL-6, IL-10, and transforming growth factor (TGF)-β; T cells promote inflammation by secreting IL-17 and inhibit inflammation-mediated tumor immune response by secreting IL-10 and TGF-β; and natural killer (NK) cells recognize and attack OSCC cells to inhibit OSCC progression. TAIC interaction network also regulates OSCC progression. M2-TAMs regulate the invasion and metastasis of OSCC by promoting T cell apoptosis through the secretion of IL-10 and programmed death-ligand (PD-L) -1, while N2-TANs inhibit T cell proliferation and cytotoxicity by secreting LOX-1 and arginase-1. MDSCs inhibit the proliferation and anti-tumor effects of CD8⁺ T cells through the inactivation of programmed cell death (PD)-1/PD-L1 signaling. Additionally, MDSCs inhibit the proliferation of T cells by decreasing the expression of the CD3-zeta chain and interferon-γ (IFN-γ). Moreover, tumor-infiltrating lymphocytes and NK cells were found to be positively correlated in OSCC progression. Therefore, target regulation, related signaling pathways, and the interaction network of TAIC may serve as promising therapeutic targets in the immunotherapy of OSCC. In this review, we summarize the recent research on the effects of TAIC and their interaction network in the TME in the progression of OSCC and explore its application in the early diagnosis and treatment of OSCC.