[Multiparametric prostate MRI for follow-up monitoring after radiation therapy]. / Multiparametrische MRT der Prostata zum Therapiemonitoring nach Strahlentherapie.

CLINICAL/METHODICAL ISSUE: Radiation therapy is a therapeutic option with curative intent for patients with prostate cancer. Monitoring of prostate-specific antigen (PSA) values is the current standard of care in the follow-up. Imaging is recommended only for symptomatic patients and/or for further therapeutic options. STANDARD RADIOLOGICAL METHODS: For detection of local recurrence magnetic resonance imaging (MRI) of the prostate is acknowledged as the method of choice. PERFORMANCE: Good results for primary diagnosis were found especially in combination with functional techniques, whereas in recurrent prostate cancer only few studies with heterogeneous study design are available for prostate MRI. Furthermore, changes in different MRI modalities due to radiation therapy have been insufficiently investigated to date. PRACTICAL RECOMMENDATIONS: As the initial results were promising prostate MRI and available therapeutic options for detection of local recurrence should be considered in patients with increased PSA.

[Imaging diagnostics of the prostate]. / Bildgebung der Prostata.

Prostate cancer is the most common malignancy of men with approximately 32,000 new cases of prostate cancer in Germany and approximately 11,000 men who would die of the disease each year. For early diagnosis of prostate cancer PSA testing is used, whereas at present screening cannot be recommended due to the lack of confirmed medical and economic benefits. Regarding the imaging modalities, ultrasound of the prostate, currently performed in combination with elastography and histoscanning, magnetic resonance imaging of the prostate in combination with endorectal coils and positron emission tomography combined with computed tomography (PET-CT) are the methods of choice. Using these methods benign prostatitis can be differentiated from prostate cancer and staging of the tumor can be accomplished. On the other hand using these imaging methods it is possible to define the dominant intraprostatic lesion with different sensitivities and specificities, which is important for minimally invasive therapeutic strategies.

Repression of the prolactin promoter: a functional consequence of the heterodimerization between Pit-1 and Pit-1 beta.

The POU-homeodomain transcription factor Pit-1 is required for the differentiation of the anterior pituitary cells and the expression of their hormone products. Pit-1beta, an alternate splicing isoform, has diametrically different outcomes when it is expressed in different cell types. Pit-1beta acts as a transcriptional repressor of prolactin (PRL) and growth hormone genes in pituitary cells, and as a transcriptional activator in non-pituitary cells. In order to explore these differences, we: (1) identified the transcriptional cofactors necessary for reconstitution of repression in non-pituitary cells; (2) tested the effect of the beta-domain on heterodimerization with Pit-1 and physical interaction with the co-activator CREB binding protein (CBP); and (3) determined the beta-domain sidechain chemistry requirements for repression. Co-expression of both Pit-1 isoforms reconstituted the repression of the PRL promoter in non-pituitary cells. The beta-domain allowed heterodimerization with Pit-1 but blocked physical interaction with CBP, and specific chemical properties of the beta-domain beyond hydrophobicity were dispensable. These data strongly suggest that Pit-1beta represses hormone gene expression by heterodimerizing with Pit-1 and interfering with the assembly of the Pit-1-CBP complex required for PRL promoter activity in pituitary cells.