Various mutations that activate NF-κB signalling have been reported in almost half of NPC cases investigated.The association between Epstein-Barr virus and nasopharyngeal carcinoma is unequivocal in World Health Organization (WHO) types II and III tumors but less well-established for WHO type I (WHO-I) NPC, where preliminary evaluation has suggested that human papillomavirus (HPV) may be associated. EBV DNA was detectable in the blood plasma samples of 96% of patients with non-keratinizing NPC, compared with only 7% in controls. The detection of nuclear antigen associated with Epstein-Barr virus (EBNA) and viral DNA in NPC type 2 and 3, has revealed that EBV can infect epithelial cells and is associated with their transformation. The cause of NPC (particularly the endemic form) seems to follow a multi-step process, in which EBV, ethnic background, and environmental carcinogens all seem to play an important role. More importantly, EBV DNA levels appear to correlate with treatment response and may predict disease recurrence, suggesting that they may be an independent indicator of prognosis. The mechanism by which EBV alters nasopharyngeal cells is being elucidated to provide a rational therapeutic target.It is also being investigated as to whether or not chronic sinusitis could be a potential cause of cancer of the nasopharynx. It is hypothesised that this may happen in a way similar to how chronic inflammatory conditions in other parts of the body, such as esophagitis sometimes leading to Barretts esophagus because of conditions such as gastroesophageal reflux disease.
An acral nevus  is a cutaneous condition of the palms, soles, fingers, or toes (peripheral body parts), characterized by a skin lesion that is usually macular or only slightly elevated, and may display a uniform brown or dark brown color, often with linear striations. : 1726 Acral nevi may occur in all ethnic groups, but are more common in dark-skinned people. The acral nevus is a benign skin lesion that can occur at any age, but is generally noticed between 10 and 30 years of age. Both children and adults may be observed with this skin lesion. The prevalence of acral nevi increases directly with degree of skin pigmentation. In a study, palmar or plantar nevi were detected in 42.0% of black (50 of 119) vs 23.0% of whites (79 of 343). Palmar or plantar nevi of 6 mm diameter or larger were detected in 3.4% of blacks (4 of 119) vs 0.6% of whites.They are brown to dark brown in color and have linear streaks of darker pigmentation. Size is usually 7 mm or less, oval or spindle shaped, and well-demarcated. They become stable after an initial growth phase, and the number of lesions also decreases; a new lesion in middle-aged or elderly people should raise suspicion of acral lentiginous melanoma. Additional image
See also
Acral lentiginous melanoma
List of cutaneous conditions

References


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