Evaluation of the Role of p53 Tumour Suppressor Posttranslational Modifications and TTC5 Cofactor in Lung Cancer.

Mutations in the p53 tumor suppressor are found in over 50% of cancers. p53 function is controlled through posttranslational modifications and cofactor interactions. In this study, we investigated the posttranslationally modified p53, including p53 acetylated at lysine 382 (K382), p53 phosphorylated at serine 46 (S46), and the p53 cofactor TTC5/STRAP (Tetratricopeptide repeat domain 5/ Stress-responsive activator of p300-TTC5) proteins in lung cancer. Immunohistochemical (IHC) analysis of lung cancer tissues from 250 patients was carried out and the results were correlated with clinicopathological features. Significant associations between total or modified p53 with a higher grade of the tumour and shorter overall survival (OS) probability were detected, suggesting that mutant and/or modified p53 acts as an oncoprotein in these patients. Acetylated at K382 p53 was predominantly nuclear in some samples and cytoplasmic in others. The localization of the K382 acetylated p53 was significantly associated with the gender and grade of the disease. The TTC5 protein levels were significantly associated with the grade, tumor size, and node involvement in a complex manner. SIRT1 expression was evaluated in 50 lung cancer patients and significant positive correlation was found with p53 S46 intensity, whereas negative TTC5 staining was associated with SIRT1 expression. Furthermore, p53 protein levels showed positive association with poor OS, whereas TTC5 protein levels showed positive association with better OS outcome. Overall, our results indicate that an analysis of p53 modified versions together with TTC5 expression, upon testing on a larger sample size of patients, could serve as useful prognostic factors or drug targets for lung cancer treatment.

Isolated penile Kaposi's sarcoma in a HIV-positive patient stable on treatment for three years.

Kaposi's sarcoma (KS) is an AIDS-defining condition. Typically, KS affects the skin with or without visceral involvement. The extensive use of antiretroviral therapy (ART) has decreased the incidence of KS amongst the HIV-positive population. We report a case of a 40-year-old man with HIV-1 infection with CD4 count of 551 cells/mm(3)and an undetectable viral load who presented with two skin-coloured KS lesions on the prepuce of the penis. Diagnosis was confirmed by histopathology. He had been commenced on ART three years earlier with a nadir CD4 count of 255 cells/mm(3) He had achieved and maintained viral suppression since commencing ART. The patient was initially treated with cryotherapy and 5% imiquimod as the lesions were presumed to be warts. The lack of response to treatment prompted further investigation. We carried out a literature search of published cases of penile KS over the past 10 years. The majority of articles regarding penile KS were published in the pre-ART era and involved patients with AIDS. Over the past 10 years, published cases of penile KS have almost exclusively been in HIV-negative men. We found 10 published cases of penile KS in HIV-negative men and only one other published case of penile KS in a HIV-positive man, who had severe immune suppression with CD4 count below 200 cells/mm(3) This is the first case report to describe a HIV-positive patient stable on ART with a CD4 count above 200 cells/mm(3)and suppressed HIV-1 viral load, to develop two KS lesions on the penis. Clinicians have to remain suspicious of penile lesions and appreciate the crucial role a biopsy with histopathological analysis plays in confirming a diagnosis. In addition, this case illustrates that unusual presentations of KS can still occur in treated HIV-positive patients with sustained immune recovery.