Pigmented trichoblastoma developed in a sebaceous nevus: HRAS mutation as a common molecular driver

Trichoblastoma Arising From the Nevus Sebaceus of Jadassohn

Trichoblastoma is a rare benign skin adnexal tumour, belonging to the category of trichogenic tumours. The clinical and histological findings may often be confused with basal cell carcinoma, a malignant epidermal skin tumour. We report here a case of a 70-year-old man presented with a dome-shaped, dark-pigmented nodule within a yellowish hairless plaque on the scalp. The plaque had existed since childhood. However, the central pigmented nodule began appearing three months ago and enlarging gradually. The patient had no medical history. Furthermore the physical examination revealed a translucent, verrucous, and yellowish plaque, with central and pigmented nodule measuring 0.7 × 0.5 cm. Also basal cell carcinoma and trichoblastoma's diagnosis were discussed. The patient was subsequently referred to the plastic surgery department, where he underwent a total excision. The histological examination was in favour of trichoblastoma arising from the nevus sebaceus. After 24 months of checking, no recurrence was observed. Trichoblastoma is a benign adnexal tumour. Its progression to malignant trichoblastoma (or trichoblastic carcinoma) is possible, but remains exceptional. Therefore, complete excision should be proposed to the patient at the time of diagnosis.

An enhanced hTERT promoter-driven CRISPR/Cas9 system selectively inhibits the progression of bladder cancer cells

The current therapies for treating tumors are lacking in efficacy and specificity. Synthetic biology principles may bring some new possible methods for curing cancer. Here we present a synthetic logic circuit based on the CRISPR/Cas9 system. The CRISPR/Cas9 technology has been applied in many biological fields, including cancer research. In this study, the expression of Cas9 nuclease was controlled indirectly by an enhanced hTERT promoter using the GAL4/upstream activating sequence (UAS) binding system. Cas9 was driven by 5XUAS, single guide RNA (sgRNA) was used to target mutant or wild-type HRAS, and the fusion gene GAL4-P65 was driven by the enhanced hTERT promoter. The system was tested in bladder cancer cells (T24 and 5637) and the results showed that the enhanced hTERT promoter could drive the expression of GAL4-P65 in these bladder cancer cell lines. Then all these devices were packed into lentivirus and the results of quantitative real-time PCR showed that the mRNA expression level of HRAS was selectively inhibited in the T24 and 5637 cells. The results of functional experiments suggested that the proliferation, cell migration and invasion were selectively suppressed, and that the apoptosis rate was increased in bladder cancer cells but not in human foreskin fibroblasts (HFF). In conclusion, we successfully constructed an enhanced hTERT promoter-driven CRISPR/Cas9 system and data showed that it could selectively suppress the progression of bladder cancer cells.