Objective · To investigate the histone methyltransferase capability of DOT1L-long form and its role in breast cancer metastasis.Methods · The existence of DOT1L-long form was confirmed by PCR, and the mRNA level of DOT1L was tested by real-time PCR. In HEK293T cells in which DOT1L canonical and DOT1L-long were overexpressed respectively, Western blotting was used to test the expression level of DOT1L and the histone methyltransferase capability. In the MCF10A cell line with inducible expression of DOT1L-long, real-time PCR was used to detect the mRNA level of epithelial-mesenchymal transition (EMT) marker, and transwell assay was used to detect the migration of breast cancer cells in which the expression level of DOT1L is low or high. Results · PCR demonstrated the existence of DOT1L-long form, and real-time PCR showed it widely exists in HCT116, T98G, MCF10A cells, etc. Western blotting showed the expression of DOT1L-long form and its H3K79 methyltransferase activity. In MCF10A cells in which overexpressed canonical DOT1L and DOT1L-long, mRNA levels of N-cadherin and fibronectine increased. Transwell showed canonical DOT1L and DOT1L-long both substantially increased the migration of breast cancer cells. Conclusion · The existence of DOT1L-long was confirmed and investigated, which is 202 amino acids longer than the canonical DOT1L, and is coded by a new exon, located between exon 27 and 28. Further, the DOT1L-long has H3K79 methyltransferase activity, and is able to promote breast cancer metastasis.

Chondrosarcoma of the chest wall is a rare primary neoplasm found to occur in elderly men. Patients present with an enlarging, painful, anterior chest wall mass arising from either the vicinity of the costochondral junction or the sternum. Treatment includes wide resection with appropriate chest wall reconstruction. We report an unusual presentation of this uncommon tumor occurring as a huge chest wall mass in a young teenage girl.
Aged ; Chondrosarcoma* ; Female ; Humans ; Male ; Ribs* ; Sternum ; Thoracic Wall*

Background: Oral cavity cancers, the second most common type in India, are responsible for 10% of the overall cancer burden. With a recurrence rate of 30% to 40% and a 5-year survival rate of 50%, these malignancies account for substantial morbidity and mortality. Despite advances in treatment modalities, survival rates following treatment completion have not improved significantly. The present study aimed to establish specific epidemiological and pathological factors responsible for recurrence after treatment completion in buccal mucosa cancers. Methods: A retrospective analysis of the data of 116 patients treated for biopsy-proven cancers of the buccal mucosa was undertaken 1 year after treatment completion. Factors such as age, sex, education, lymphovascular invasion, extranodal extension (ENE), perineural invasion, depth of invasion, and pathological margin status were compared between patients who presented with recurrence and those who did not. Statistical significance was set at p< 0.05. Results: Of the 116 patients, 40 (34.5%) developed a recurrent disease within 1 year. The mean age of the study population was 43.3 years, and males constituted 91.4% of the included patients. Ipsilateral buccal mucosa was the commonest site of disease recurrence. Neck node metastasis, ENE, and margins of resection < 5 mm were significantly related to the recurrence of disease. However, surprisingly, lymphovascular invasion, perineural invasion, and depth of invasion > 10 mm did not show statistically significant associations. Conclusion Neck node metastasis, ENE, and margins of resection < 5 mm were the histopathological factors associated with recurrence in cancers of the buccal mucosa.