Mutations of the p53 gene in nasal NK/T-cell lymphoma.

Mutations of the p53 tumor suppressor gene are reported in various kinds of malignancies including lymphomas. However, p53 gene mutations in nasal NK/T-cell lymphoma have not been reported because most parts of tumors are necrotic and a small amount of living tumor tissues is available for the molecular study. Expression and mutations of the p53 gene were examined in the paraffin-embedded specimens of the nasal lesions from 42 Chinese (Beijing and Chengdu) and Japanese (Okinawa and Osaka) patients with nasal NK/T-cell lymphoma by the immunohistochemistry and single strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) amplified products followed by direct sequencing. Thirty single-nucleotide substitution mutations were observed in 20 of 42 cases (47.6%). Among the 30 mutations, 18 were missense (mainly G:C to A:T transitions), 9 were silent, and 1 was a nonsense mutation. The remaining 2 mutations involved intron 5 and exon 5 terminal points. Abnormal expression of the p53 protein was also observed in 19 of 42 (45.2%) cases. The incidence was significantly (4-fold) higher in the cases of Osaka than those in other areas, although the incidence of p53 mutations in the cases of Osaka was one-half to one-third of those in the other three areas. The results may suggest some racial, environmental, or lifestyle differences in the cause of nasal tumorigenesis.

Chronological changes in incidences of polymorphic reticulosis in Korea and Japan.

Lethal midline granuloma (LMG) is a clinical term, which describes a group of diseases histologically comprising Wegener's granulomatosis, polymorphic reticulosis (PR), and malignant lymphoma of the ordinary type (ML). PR is a variant of ML, and is considered to be a type of NK/T cell lymphoma. Our previous study revealed the clustering of patients with PR in East Asia including China, Korea and Japan. However, the frequency rate of PR varied even among these countries, with that of Korea being approximately 5 times higher than that of Japan. In the present study, we examined the incidences of each type of LMG, especially PR, in Korea (Yonsei University) and Japan (59 university hospitals) over time. A total of 102 cases and 655 cases of LMG admitted to Yonsei University, Korea from 1977 to 1996 and 59 university hospitals in Japan between 1965 and 1996, respectively, were examined. The frequency rate of PR per 100,000 outpatients of ears, nose and throat (ENT) clinics in Korea decreased from 40 to 20 between the periods of 1977-1989 and 1990-1996. However, there were no significant changes in Japan during the period studied.

Risk of non-Hodgkin's lymphoma in patients with hepatitis C virus infection.

Hepatitis C virus (HCV) has been suggested to play an etiological role in the development of B-cell non-Hodgkin's lymphoma (NHL) in Italy. However, another study in Scotland questioned increased risk of development of NHL in patients with chronic HCV infection. A total of 2,162 patients admitted to 3 hospitals in Osaka, where the incidence of HCV-related hepatitis is highest in Japan, during the period from 1957 to 1997 were followed up from the date of diagnosis of chronic HCV-related hepatitis until 30 October 1997. Overall, 12,404.5 person-years of observation were accrued with a follow-up period ranging from 0.25 to 40.4 (average 5.74) years. NHL of the B-cell type developed in 4 patients. The interval between onset of chronic HCV and NHL ranged from 6 to 36 (median 13) years. Expected number of cases of NHL in the sex-, age- and calendar year-matched general population was 1.90, which gave a relative risk (RR) of 2.10 (95% confidence interval 0.57-5.38; p = 0.247). Taking the much higher RR for hepatocellular carcinoma among patients with HCV infection into account, chronic HCV infection was considered to be moderately associated with increased risk of NHL.

Characteristics of non-Hodgkin's lymphoma complicated by renal cell malignancies.

Previous epidemiological studies showed an increased risk for the development of renal cell carcinoma (RCC) after adjuvant therapy or simultaneous discovery of non-Hodgkin's lymphoma (NHL). However, clinicopathological features of NHL complicated by RCC are not well known. We summarized the clinicopathological features of 42 cases with malignant lymphoma complicated by renal tumors collected in a nationwide study in Japan. There were 27 males and 15 females, and the age at initial diagnosis of NHL ranged from 51 to 85 years (median 69 years). The clinical stages of NHL were stage I in 13 patients, stage II in 8, stage III in 8 and stage IV in 13 patients. RCC was simultaneously detected in 4 patients, within 1 year after the diagnosis of NHL in 20 and after more than 1 year in 13 patients. In the remaining 3 patients, NHL was diagnosed 1 year (2 cases) or 6 years (1 case) after nephrectomy. Histologically, all but 2 cases of NHL were diagnosed as diffuse lymphoma, with the large-cell type being the most common. The remaining 2 cases were follicular lymphoma. NHL in 35 cases (85%) were immunophenotyped as B cell type and 4 (10%) as T cell type. Renal tumors in all but 2 cases were classified as RCC: clear-cell type in 29, chromophobic type in 3, chromophilic type in 7 and Bellini duct carcinoma in 1 case. All RCC showed a cellular malignancy of grade II or III. When compared to sporadic autopsy cases of NHL in Japan, the frequency of extranodal lymphoma and B cell type was higher in the current cases (p = 0.06). In addition, leiomyosarcoma occasionally occurred among complicated renal tumors.