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Extranodal NK/T-cell lymphoma (ENKTL), nasal type is an aggressive lymphoma characterized by rapid clinical progression, an unfavorable prognosis, and a short survival time. This study aimed to investigate the correlations of c-MYC protein expression, gene rearrangement, and gene copy number with the prognosis of ENKTL. Immunohistochemistry for CD20, CD3, CD56, TIA-1, Ki-67, and c-MYC were performed using tissue sections from 68 patients diagnosed with ENKTL. In situ hybridization was performed to detect Epstein-Barr virus (EBV)-encoded small RNA (EBER). c-MYC genetic alterations (located on chromosome 8q24) were detected using fluorescence in situ hybridization. Sixty patients with nasopharyngeal mucosa lymphadenosis were selected as a normal control group for the c-MYC gene and protein. Immunophenotypically, CD3 and TIA-1 were positive in all patients, CD56 was positive in 54 patients (79.4%), and CD20 was negative in all patients. A Ki-67 proliferation index of > 50% was observed in 94.1% of patients (64/68). In situ hybridization for EBER was positive in all patients. The c-MYC positive expression rate (> 40% of tumor cells with nuclear staining regarded as positive) in patients with ENKTL was 50% (34/68), which was significantly higher than that in patients with nasopharyngeal mucosa lymphadenosis (0%, 0/60; p 0.05). Multivariate Cox regression analysis further confirmed that clinical stage and c-MYC positivity were independent prognostic factors in patients with ENKTL. The abnormal expression of c-MYC may play an important role in the development and progression of ENKTL and influence the prognosis of patients.

A perturbation variational approach to atomic behavior in strong laser fields is expressed briefly. For a wide range of , the ground state energy of H atom in laser fields is obtained by the application of the perturbation variational approach. The obtained energy values agree with the previous values given by T. C. Landgraf and M. Gavrila. According to the obtained energy values, a new value of limit of validity of traditional radiation-perturbation theory (TRPT) is given.

A new analytic model for the above threshold ionization spectrum of He in a circularly polarized laser field is proposed. The experimental spectrum obtained by Mohideen et al. can be quite well described by this model. The spectra predicted by our model agree with experiment better than those of Reiss when the spatiotemporal profile of the laser pulse is taken into account and better than those of the Keldysh-Faisal-Reiss theory when the profile is not taken into account. At the same time, we find that the experimental value of the peak laser intensity was overstated by a factor of about 5. This result supports the previous similar claim by Reiss.