Objective:To explore whether spontaneous sene-scence widely existed in malignant tumor cells. Methods:Sene-scence-associated beta-galactosidase (SA-β-Gal) staining kit was used to detect the activity of SA-β-Gal in ten different malignant tumor cell lines before and after serum deprivation. Results:SA-β-Gal was expressed in some cells of 10 malignant tumor cell lines during exponential growth phase without any treatment. However, the percentage of senescent cells was significantly different among them, the lowest expression was observed in HeLa cell line (0.65%), and the highest expression was seen in HepG2 cell line (3.69 %, F=13.006, P= 0.000). Furthermore, not all the SA-β-Gal positive aging cells were polyploid cells. After 24-h serum deprivation, the number of SA-β-Gal positive cells was significantly increased (P=0.001). Conclusion:These findings indicate that immortal malignant tumor cell lines could undergo spontaneous senescence but the level was different between various cell lines. Short-term serum de-privation significantly increased the percentage of aging cells indicating that serum deprivation-induced cell senescence may be a rapid, easy, and effective way for anti-tumor therapy.

Purpose To investigate the mutations of ID3,TCF3 and MYC genes in Chinese Burkitt lymphoma and discuss their significance.Methods Total DNA was extracted from tumor tissues of 32 patients with Burkitt lymphoma,then the DNA was amplified by polymerase chain reaction (PCR),and the products of PCR were sequenced directly with Sanger sequencing methods.Results The mutation rates of ID3 and TCF3 genes were 35.5％ (11/31) and 18.8％ (6/32) respectively.The mutation rate of MYC was 50％.The mutation rates of MYC exon 1,MYC exon 2 and MYC exon 3 were 3.3％ (1/30),50％ (15/30) and 7.7％ (2/26) respectively.Conclusion Recurrent mutations of the ID3,TCF3 and MYC genes in Chinese Burkitt lymphoma were identified by Sanger sequencing.For TCF3 gene,a novel mutation c.2202G ＞ C p.L569V was found in three cases.In two cases,a novel mutation of c.1070A ＞G p.G182D was found in MYC gene.

Objective:To investigate the clinicopathological, immunohistochemical and molecular genetic characteristics of TFE3-rearranged perivascular epithelioid cell tumor (PEComa).Methods:Eight cases of PEComa with TFE3 rearrangement diagnosed in the First Affiliated Hospital of Air Force Medical University from January 2014 to July 2022 were collected. Three were consultation cases and 5 were collected from our hospital; 7 cases were resection specimens and 1 case was a needle biopsy specimen. Routine histolopathological analysis, immunohistochemical staining, fluorescence in situ hybridization (FISH) and the next-generation sequencing were performed. Clinical data were collected and the prognosis was assessed.Results:The 8 patients consisted of 5 females and 3 males with a median age of 45 years (ranged from 25 to 65 years). The tumor location included 1 uterus, 1 liver, 1 urachus, 2 kidneys, 1 abdominal cavity, 1 colon, and 1 retroperitoneum (3 subsequent recurrences in the abdominal cavity, pelvis and ovary, and abdominal cavity, respectively). Morphologically, the tumor cells were uniform and epithelioid with translucent or eosinophilic cytoplasm. They were arranged in nests or sheets, most of which were separated by thin-walled blood vessels. There were no papillary structures, and no overt smooth muscle or fat components. Atypical features were seen in 3 cases, with bizarre nuclei and tumor giant cells. Large areas of necrosis were visible, and mitosis was common (up to 28/50 HPF). Melanin deposition was present in 3 cases. Immunohistochemical staining showed diffuse and strong positivity for TFE3 in 8/8 cases and for HMB45 in 6/8 cases; focal positivity for Cathepsin K and Melan-A in 6/8 cases and for SMA in 2/8 of cases. All cases were negative for CKpan, PAX8 and Desmin. TFE3 gene break-apart was detected by FISH in all 8 cases, 4 of which underwent next-generation sequencing, and it revealed that 2 cases presented with SFPQ::TFE3 fusion, 1 case with ASPSCR1::TFE3 fusion, and 1 case with no chimeric fusion. Seven cases were followed up for 4—94 months. All cases were alive; 4 cases were disease-free, 2 cases showed recurrence, and 1 case had metastasis at initial diagnosis.Conclusions:TFE3-rearranged PEComa has unique histomorphological, immunohistochemical and molecular characteristics. The biological behavior is aggressive, which could lead to recurrence and metastasis, and warrants close clinical follow-up.