LncRNAs are involved in the occurrence and progressions of multiple cancers. Emerging evidence has shown that PCAT6, a newly discovered carcinogenic lncRNA, is abnormally elevated in various human malignant tumors. Until now, PCAT6 has been found to sponge various miRNAs to activate the signaling pathways, which further affects tumor cell proliferation, migration, invasion, cycle, apoptosis, radioresistance, and chemoresistance. Moreover, PCAT6 has been shown to exert biological functions beyond ceRNAs. In this review, we summarize the biological characteristics of PCAT6 in a variety of human malignancies and describe the biological mechanisms by which PCAT6 can facilitate tumor progression. Finally, we discuss its diagnostic and prognostic values and clinical applications in various human malignancies.

Background:The standard treatment for most localised breast cancer patients is the breast-conservating sugery followed by postoperative radiation worldwide. Preliminary studies of intraoperative radiotherapy with electrons(ELIOT) in selected patients, mainly in Europe since 1999, have shown good local control, less toxicity and satisfatory cosmetic apperance. However few studies have been conducted among non-western populations. To investigate the feasibility of ELIOT in China, we introduced ELIOT in selected early breast cancer patients. Risk of local relapse is the main outcome objective, toxicity and cosmetic results are also studied. Patients and Methods:From June 2007 to May 2010, 51 patients diagnosed with unifocal breast carcinoma up to a diameter of 3cm received a wide excision of the primary tumor followed by a radiotherapy of 21Gy delivered to the breast tissue at the surface of the tumor bed, biologically equivalent to 58 to 60 Gy in standard fractionation. The median age of the treated patients was 47 years, with 38/51(74.5%) patients younger than 50. 8 patients(15.7%) were found to have positive axillary I-nodes(six patients had one node involved, one patient had two and one had three positive nodes). Pathologic free margins ≥10 mm were obtained in all patients. Patients were evaluated semiannunally after surgery, and thereafter every 6 months for cosmetic results, complications and other events. Results: After a follow-up from 4 to 36 months(median time12 months), 3 patients developed fat deliquescence, 16 patients showed wound edema and excess fluid and no one had incision infection or hematoma. Two patients developed local relapses. One was comfirmed unrecognised multi-focal cancer in other quadrants of the breast remain dormant. The other patient was confirmed ipsilateral positive axillary III-nodes and no relapse was found in the same quadrant. Neither contralateral breast cancer nor distant metastases were observed. No replase was found in patients aged <50. Accodring to the JCRT standard, cosmetic result was excellent in 73.1% and 90.9% patients at one year and two year checkup respectively, and good was found in 15.4% and 9.1% patients. Conclusion:The incidence of breast cancer remains to increase in China with the aging of society and changes of lifestyle, and the highest incidence is found in the age group 45-50 years.Our study suggested the toxicity and cosmetic evalution were good. Data on local control were encouraging, especially for those under 50. ELIOT of 21Gy was a well-tolerated treatment in early stage Chinese breast cancer patients. And further follow up is still needed. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-10.