114. Klasyfikacja nowotworów pęcherza moczowego – podstawy kliniczne i molekularne

Klasyfikacje nowotworów pęcherza moczowego, a w szczególności brodawkowatych rozrostów powierzchownych budzi liczne kontrowersje. Klasyfikacja WHO z 1999 roku, obok brodawczaka i raków brodawkowatych G1– G3, wprowadziła nową jednostkę – papillary urothelial neoplasm of low malignant potential (PUNLMP), co spowodowało poszerzenie tej grupy do pięciu jednostek. Podział nie został powszechnie zaakceptowany, a dane literaturowe na temat jego celowości są rozbieżne. Poprzednia klasyfikacja WHO z 1973 roku wyróżniała jedynie brodawczaki i trzy stopnie raka brodawkowatego. Jednakże badania uropatologów skandynawskich (Berkvist, Malstrom i inni) wykazały, że grupa raka G-1 jest heterogenna i zawiera dwie jednostki o nieco różnym rokowaniu. Ta argumentacja została przyjęta przez konsensus WHO/ISUP i wdrożona w klasyfikacji WHO z 1999 roku, gdzie „stare” raki G1 podzielono na PUNLMP i raki G-1. Brodawczaki pozostały z przypisanym im bardzo dobrym rokowaniem (brak progresji, nieliczne nawroty). Opinie na temat zasadności podziału pozostałych nowotworów na cztery grupy są różne. Część autorów znalazła różnice w rokowaniu (nawroty, progresja) pomiędzy PUNLMP i rakami G1, G2 i G3. Inni badacze nie potwierdzili tych doniesień. Pojawiły się także prace dowodzące, że ani klasyfikacja WHO 73’ ani WHO 99’ nie pozwala na wykazanie statystycznie istotnych różnic w ocenie progresji i rokowania. Jednak już klasyfikacja WHO 99’ zwraca uwagę, że podstawowe znaczenie ma odróżnienie nowotworów o niskiej złośliwości (PUNLMP i rak G-1) od nowotworów o wysokiej złośliwości (rak G2 i G3). Stoi to nadal w sprzeczności z częścią doniesień, jednak odpowiada podziałom proponowanym przez autorów amerykańskich (Murphy, AFIP). Za takim podziałem przemawiają badania molekularne, które wykazały, że nowotwory z grupy low-grade mają inne zmiany niż nowotwory bardziej agresywne. Zarówno w guzach low-grade jak i w brodawczakach stwierdza się nieliczne zmiany genomowe (głównie chromosomu 9), diploidię i mutacje aktywacyjne FGFR3, gdy natomiast raki G-2 i G-2 częściej mają liczne zmiany w genach (różne chromosomy), są poliploidalne i rzadko stwierdza się mutacje FGFR3. Ta ostatnia obserwacja nakazuje zapytać, czy na pewno guzy o wysokiej złośliwości powstają na podłożu zmian o niższej złośliwości czy też tworzą się niezależnie. Przygotowana obecnie klasyfikacja WHO 2004 pozostawia papilloma i PUNLMP dzieląc raki brodawkowate jedynie na dwie grupy. Wydaje się, że badania molekularne i dokładne badania kliniczne mogą na końcu doprowadzić do połączenia tych jednostek tylko w dwie, różne rokowniczo grupy. Z drugiej strony trzeba pamiętać, że każda klasyfikacja jest nie tyle ustaleniem prawdy co ustaleniem kompromisu, a o to może być jeszcze długo bardzo trudno

Elimination of wild-type P53 mRNA in glioblastomas showing heterozygous mutations of P53

We screened 50 glioblastomas for P53 mutations. Five glioblastomas showed heterozygous mutations, while three were putatively heterozygous. Six of these eight glioblastomas showed elimination of wild-type P53 mRNA. These results strongly suggest that some sort of mechanism(s) favouring mutated over wild-type P53 mRNA exists in glioblastoma cells with heterozygous mutations of this gene

cDNA sequencing improves the detection of P53 missense mutations in colorectal cancer

<p>Abstract</p> <p>Background</p> <p>Recently published data showed discrepancies beteween <it>P53 </it>cDNA and DNA sequencing in glioblastomas. We hypothesised that similar discrepancies may be observed in other human cancers.</p> <p>Methods</p> <p>To this end, we analyzed 23 colorectal cancers for <it>P53 </it>mutations and gene expression using both DNA and cDNA sequencing, real-time PCR and immunohistochemistry.</p> <p>Results</p> <p>We found <it>P53 </it>gene mutations in 16 cases (15 missense and 1 nonsense). Two of the 15 cases with missense mutations showed alterations based only on cDNA, and not DNA sequencing. Moreover, in 6 of the 15 cases with a cDNA mutation those mutations were difficult to detect in the DNA sequencing, so the results of DNA analysis alone could be misinterpreted if the cDNA sequencing results had not also been available. In all those 15 cases, we observed a higher ratio of the mutated to the wild type template by cDNA analysis, but not by the DNA analysis. Interestingly, a similar overexpression of <it>P53 </it>mRNA was present in samples with and without <it>P53 </it>mutations.</p> <p>Conclusion</p> <p>In terms of colorectal cancer, those discrepancies might be explained under three conditions: 1, overexpression of mutated <it>P53 </it>mRNA in cancer cells as compared with normal cells; 2, a higher content of cells without <it>P53 </it>mutation (normal cells and cells showing <it>K-RAS </it>and/or <it>APC </it>but not <it>P53 </it>mutation) in samples presenting <it>P53 </it>mutation; 3, heterozygous or hemizygous mutations of <it>P53 </it>gene. Additionally, for heterozygous mutations unknown mechanism(s) causing selective overproduction of mutated allele should also be considered. Our data offer new clues for studying discrepancy in <it>P53 </it>cDNA and DNA sequencing analysis.</p

Basal keratin expression in breast cancer by quantification of mRNA and by immunohistochemistry

Definitions of basal-like breast cancer phenotype vary, and microarray-based expression profiling analysis remains the gold standard for the identification of these tumors. Immunohistochemical identification of basal-like carcinomas is hindered with a fact, that on microarray level not all of them express basal-type cytokeratin 5/6, 14 and 17. We compared expression of cytokeratin 5, 14 and 17 in 115 patients with operable breast cancer estimated by real-time RT-PCR and immunohistochemistry

Altered expression of the suppressors PML and p53 in glioblastoma cells with the antisense-EGF-receptor

Gene amplification and enhanced expression of the epidermal growth factor receptor (EGFR) represent the major molecular genetic alteration in glioblastomas and it may play an essential role in cell growth and in the carcinogenic process. On the other hand, the nuclear suppressor proteins PML and p53 are also known to play critical roles in cancer development and in suppressing cell growth. Here we report that, in glioblastoma cells with defective EGFR function, the expressions of both promyelocytic leukaemia (PML) and p53 were altered. Cells that were transfected with the antisense-cDNA of EGFR were found to have more cells in G1 and fewer cells in S phase. In addition, the transfected cells were found to be non-responsive to EGF-induced cell growth. Interestingly, the expression of the suppressors p53 and PML were found to be significantly increased by immunohistochemical assay in the antisense-EGFR cells. Moreover, the PML expression in many of the cells was converted from the nuclear dot pattern into fine-granulated staining pattern. In contrast, the expressions of other cell cycle regulated genes and proto-oncogene, including the cyclin-dependent kinase 4 (cdk4), retinoblastoma, p16INK4a and p21H-ras, were not altered. These data indicate that there are specific inductions of PML and p53 proteins which may account for the increase in G1 and growth arrest in antisense-EGFR treated cells. It also indicates that the EGF, p53 and PML transduction pathways were linked and they may constitute an integral part of an altered growth regulatory programme. The interactions and cross-talks of these critical molecules may be very important in regulating cell growth, differentiation and cellular response to treatment in glioblastomas. © 1999 Cancer Research Campaig

Does vimentin help to delineate the so-called 'basal type breast cancer'?

<p>Abstract</p> <p>Background</p> <p>Vimentin is one of the cytoplasmic intermediate filament proteins which are the major component of the cytoskeleton. In our study we checked the usefulness of vimentin expression in identifying cases of breast cancer with poorer prognosis, by adding vimentin to the immunopanel consisting of basal type cytokeratins, estrogen, progesterone, and HER2 receptors.</p> <p>Methods</p> <p>179 tissue specimens of invasive operable ductal breast cancer were assessed by the use of immunohistochemistry. The median follow-up period for censored cases was 90 months.</p> <p>Results</p> <p>38 cases (21.2%) were identified as being vimentin-positive. Vimentin-positive tumours affected younger women (p = 0.024), usually lacked estrogen and progesterone receptor (p < 0.001), more often expressed basal cytokeratins (<0.001), and were high-grade cancers (p < 0.001). Survival analysis showed that vimentin did not help to delineate basal type phenotype in a triple negative (ER, PgR, HER2-negative) group. For patients with 'vimentin or CK5/6, 14, 17-positive' tumours, 5-year estimated survival rate was 78.6%, whereas for patients with 'vimentin, or CK5/6, 14, 17-negative' tumours it was 58.3% (log-rank p = 0.227).</p> <p>Conclusion</p> <p>We were not able to better delineate an immunohistochemical definition of basal type of breast cancer by adding vimentin to the immunopanel consisted of ER, PgR, HER2, CK5/6, 14 and 17 markers, when overall survival was a primary end-point.</p