Aberrant Methylation of p21 Gene in Lung Cancer and Malignant Pleural Mesothelioma

Suppression of p21 has been implicated in the genesis and progression of many human malignancies. DNA methylation is an important mechanism of gene silencing in human malignancies. In this study, we examined the expression status and aberrant methylaion of p21 in lung cancers and malignant pleural mesotheliomas (MPM). We used 12 small cell lung cancer (SCLC) cell lines, 13 non-small cell lung cancer (NSCLC) cell lines, 50 primary NSCLCs, 6 MPM cell lines and 10 primary MPMs. The expression and methylation of p21 was examined by reverse transcription-PCR (RT-PCR), Western blotting and methylation-specific PCR (MSP) assay. Loss of p21 protein expression was observed in 7 SCLC cell lines (58.3%), 5 NSCLC cell lines (38.5%) and 3 MPM cell lines (50%) while mRNA expression was lost in 2 SCLC cell lines (16.7%), 2 NSCLC cell lines (15.4%) and none of the MPM cell lines. Aberrant methylation of p21 was found in 8.3% of SCLC cell lines, 30.2% of NSCLCs and 6.3% of MPMs. Among primary NSCLCs, methylation in adenocarcinomas was significantly more frequent than in squamous cell carcinomas. Loss of p21 expression was frequently observed in lung cancers and MPMs and aberrant methylation was one of the mechanisms of suppression of p21, especially in NSCLCs

Complete spontaneous necrosis of hepatocellular carcinoma confirmed on resection: A case report

Introduction: Complete spontaneous necrosis of hepatocellular carcinoma (HCC) without any pretreatment or angiography is rare. We present a rare case of spontaneous complete necrosis of HCC, as confirmed after hepatectomy. Presentation of case: The patient, a 74-year-old man with a history of alcoholic hepatitis, was referred to our hospital for confirmation of suspected HCC. In March 2015, abdominal ultrasonography detected a low echoic mass in segment 8 (S8) of the liver. Contrast-enhanced computed tomography (CT) imaging revealed interval growth of this tumor and showed that the tumor was well enhanced in the arterial phase and washed out in the portal and delayed phases. The serum alpha-fetoprotein level was elevated at 30.8 ng/mL and the percentage of the L3 isoform was 25.5%. Two months later, CT imaging showed that the tumor was of low density and had decreased in size; no contrast enhancement of the tumor was seen. Spontaneous necrosis of the HCC was considered; however, as we could not exclude viable malignant cells in the tumor, we performed S8 segmentectomy of the liver. The resected tumor specimen had a thick fibrous capsule. Histopathological findings showed only granulation and necrotic tissue accompanied by bleeding and hemosiderosis. No viable tumor cells were observed. The serum alpha-fetoprotein level returned to the normal range one month after surgery. Discussion: If spontaneous regression has occurred, there is a possibility of HCC recurrence and of remnant viable tumor cells. Conclusion: We present a rare case of complete spontaneous necrosis of HCC and strongly recommended surgical intervention