Histopathologie des Harnblasenkarzinoms: Entscheidend für das Management der betroffenen Patienten

[Preneoplastic lesions and precursors of urothelial cancer]

As even a mere thickening of the urothelium can harbor genetic changes identical to that of low grade papillary urothelial tumors, it is not always possible to clearly recognize a precursor lesion of urothelial carcinoma by routine histological diagnostics. Complementary immunohistochemical and molecular diagnostic methods assist the recognition of these entities. These methods especially help to identify clinically important genetically unstable cells as the hallmark of carcinoma in situ (CIS). Little is known about the clinical significance of the morphological subtypes of CIS, which range from large cell to micropapillary variants. For a better understanding of special types of bladder cancer (e.g. adenocarcinoma and squamous cell carcinoma), it seems to be important to define the phenotype and the molecular pattern of non-urothelial lesions, such as intestinal metaplasia and squamous metaplasia, better and more precisely.

Proteomic tissue profiling for the improvement of grading of noninvasive papillary urothelial neoplasia

OBJECTIVES

In 2004, a novel grading system for papillary non-invasive bladder cancer was introduced; low grade (LG) and high grade (HG) in lieu of the former G1, G2, G3. This change allowed for increased reproducibility as well as diminished interobserver variability in histopathological grading among individual pathologists. Matrix Assisted Laser Desorption/Ionization Time of Flight Imaging Mass Spectrometry (MALDI TOF IMS) was evaluated as an automatic and objective tool to assist grading of urothelial neoplasms and to facilitate accuracy.

DESIGN AND METHODS

To separate G1 (LG, n=27) and G3 (HG, n=21) papillary tumors MALDI TOF IMS was performed using an appropriate algorithm. Thereafter, the automatic assignment of a separate G2 (n=31) group was completed.

RESULTS

G1 (LG) and G3 (HG) tumors were separated with an overall cross validation of 97.18%. G2 tumors indicated a true positive rate of 78.3% for LG and 87.5% for HG, respectively.

CONCLUSIONS

MALDI TOF IMS is a powerful support tool to ascertain pathological diagnosis/grading.

[Update on urothelial carcinoma histopathology]

Urothelial carcinoma comprise a heterogenous group of diseases with very different clinical outcome: 70%-80% of urothelial carcinoma are genetically stable and associated with a favorable prognosis, while 20%-30% are genetically unstable and have a high progression rate. Therefore, the current WHO Classification (2004) reduces the histologic grade to simply 'low grade' and 'high grade'. In addition to TNM classification and histologic grade, genetic factors such as p53 mutations, fibroblast growth factor receptor 3 (FGFR3) and phosphatidylinositol-3-kinase (PIC(3)CA) are relevant in a patient's prognosis.