Tumor initiation and early tumorigenesis: molecular mechanisms and interventional targets.

Tumorigenesis is a multistep process, with oncogenic mutations in a normal cell conferring clonal advantage as the initial event. However, despite pervasive somatic mutations and clonal expansion in normal tissues, their transformation into cancer remains a rare event, indicating the presence of additional driver events for progression to an irreversible, highly heterogeneous, and invasive lesion. Recently, researchers are emphasizing the mechanisms of environmental tumor risk factors and epigenetic alterations that are profoundly influencing early clonal expansion and malignant evolution, independently of inducing mutations. Additionally, clonal evolution in tumorigenesis reflects a multifaceted interplay between cell-intrinsic identities and various cell-extrinsic factors that exert selective pressures to either restrain uncontrolled proliferation or allow specific clones to progress into tumors. However, the mechanisms by which driver events induce both intrinsic cellular competency and remodel environmental stress to facilitate malignant transformation are not fully understood. In this review, we summarize the genetic, epigenetic, and external driver events, and their effects on the co-evolution of the transformed cells and their ecosystem during tumor initiation and early malignant evolution. A deeper understanding of the earliest molecular events holds promise for translational applications, predicting individuals at high-risk of tumor and developing strategies to intercept malignant transformation.

Grisel's syndrome associated with mumps: A case report.

Grisel's syndrome (GS) is defined as atlantoaxial rotatory subluxation/fixation not associated with trauma or bone disease, usually following head and neck infection/inflammation or ear, nose, and throat (ENT) surgery. Many conditions could lead to Grisel's syndrome, of which mumps is rarely to be seen. This report discusses a case of GS in children with Type I atlantoaxial joint subluxation and previously diagnosed mumps. A 6-year-old boy who had cervical pain and torticollis for 2 weeks was admitted to our hospital. There was no trauma and he had not had ENT surgery but was diagnosed with mumps 2 weeks previously due to swelling of the left cheek and cervical lymph node. Physical examination and computed tomography confirmed a diagnosis of Grisel's syndrome with an ADI (atlanto-dens interval) of 1.6 mm. The patient then received occipito-mandibular traction for 6 days and recovered. No recurrence was observed at 1 year follow-up. Physicians should raise awareness of this rare complication of mumps to avoid life-threatening neurological impairments owing to Grisel's syndrome.