Claus Dieter Gerharz

Distinct in vivo expression patterns of survivin splice variants in renal cell carcinomas

Survivin, a novel member of the inhibitor of apoptosis protein (IAP) family, reduces the susceptibility of tumor cells to proapoptotic stimuli, thereby promoting tumor cell survival during tumor progression and treatment with anticancer drugs. Recently, we identified 2 novel alternative splice variants of survivin, survivin‐2B and survivin‐ΔEx3, which differ in their antiapoptotic properties. Survivin‐2B has lost its antiapoptotic potential and may act as a naturally occurring antagonist of antiapoptotic survivin and survivin‐ΔEx3. Because the in vivo expression of these splice variants in human cancer has not been analyzed so far, 57 renal cell carcinomas (RCCs) were explored using quantitative reverse transcriptase polymerase chain reaction. We found that all RCCs express survivin‐ΔEx3, survivin‐2B and survivin, the latter being the dominant transcript. When we compared early and intermediate stages with late stages of clear cell RCCs, no significant changes in the expression levels of survivin and survivin‐ΔEx3 became evident. However, a significant decrease was observed for the mRNA ratio between survivin‐2B and survivin in late tumor stages (p = 0.036). Chromophilic/papillary RCCs, which are known to be less aggressive than clear cell RCCs, did not show significantly lower expression levels of antiapoptotic survivin and survivin‐ΔEx3, compared with stage‐adjusted clear cell RCCs. Our study demonstrates for the first time in vivo expression of functionally different survivin variants and suggests a role of these survivin splice variants in the progression and clinical behavior of human RCCs.

Staging of Pelvic Lymph Nodes in Neoplasms of the Bladder and Prostate by Positron Emission Tomography with 2-[18F]-2-Deoxy-D-Glucose

Objectives: The aim of this study was to evaluate whether pelvic lymph node metastases in patients with neoplasms of the bladder or prostate can be detected applying positron emission tomography with 2-[18F]-2-deoxy-D-glucose (FDG-PET). Methods: Eight patients with bladder cancer and 17 patients with prostate cancer were examined with FDG–PET before pelvic lymph node dissection. Results of PET were then compared to histology of pelvic lymph nodes obtained at surgery. Results: Lymph node metastases were detected by histopathological examination in 3 patients with bladder cancer and in 6 patients with prostate cancer. At the sites with histologically proven metastases, increased FDG uptake suspicious of metastatic disease was found in 2/3 and 4/6 patients, respectively. The smallest detected metastasis was a micrometastasis with a diameter of 0.9 cm. In 3 additional patients who all had histopathologically proven micrometastases (∅ ≤0.5 cm), FDG uptake was within the normal range. No false-positive results were obtained. Conclusions: These results suggest that FDG-PET may be a valuable diagnostic tool in the staging of pelvic lymph nodes in bladder and prostate cancer.

Positron-emission tomography with 18F-2-fluoro-2-deoxy-D-glucose (18FDG-PET) in the diagnosis of retroperitoneal lymph-node metastases from testicular tumors

SummaryIn 1991, this prospectively designed study was started to assess the potentials of positron emission tomography with 18FDG in the diagnostic workup for the detection of lymph node metastases in testicular cancer, since there were no data available concerning this subject at this time. In 54 patients (27 patients with pure seminoma, 27 patients with non-seminomatous tumors) 18FDG-PET results were compared with the findings obtained with abdominal computed tomography, serum level of tumor markers (AFP, β -HCG), and the histopathological findings after primary or post-chemotherapy retroperitoneal lymph node dissection. In 21 patients with pure seminoma (clinical stage I according to the Lugano classification) 18FDG-PET results were identical with those of the abdominal computed tomography, so PET does not add relevant informations in this group of patients. In 7 patients presenting with non-seminomatous testicular cancer (stage I), PET was not able to detect the existing micrometastases in 4 patients. In 1/7 case PET examination showed a suspicious focal lesion, this lymph node had 2 micrometastases within inflammatory changes. In 1/7 patient 18FDG-PET definitely revealed metastatic lesions, while the CT scans where judged to be unobtrusive and tumor marker levels were within the normal range. In the 4 patients with pure seminomas stage II B and II C (N = 6), that have undergone retroperitoneal lymph node dissection following chemotherapy, 18FDG-PET correctly predicted absence of tumor in 3 out of these 4, and in 1/4 patient the benign nature of a persistent large tumor after two cycles of polychemotherapy was correctly identified wich eventually turned out to be a ganglioneuroma. This lesion falsely was classified as malignant tumor with abdominal computed tomography, and in 2/4 patients post-chemotherapy residual retroperitoneal lesions in the CT scans could not be assessed exactly whether or not malignant tumor was present. In 20 patients presenting with non-seminomatous testicular cancer (stage II and III) 18FDG-PET was able to demonstrate therapeutic effects of chemotherapy by showing decreasing tracer activity in those regions, that had hypermetabolic foci prior to chemotherapy. It became evident in testicular cancer that there is a single entity which is not characterized by increased glucose metabolism, the mature teratoma. In lesions detected by abdominal computed tomography which do not present increased 18FDG uptake, mature teratoma as well as scar/necrosis or rare other tumors with normal glucose metabolism can be supposed, but additional characteristics based on different 18FDG uptake were not observed. In 1/20 case post-chemotherapy PET scan detected a hypermetabolic lesion, which was suspicious for metastatic spread, but in the histopathological examination this lesion was identified as inflammatory tissue reaction. Based on the data reported here in 18FDG-PET cannot be considered a standard diagnostic tool in the staging examinations in testicular cancer. It is of clinical relevance in patients who present residual tumor after chemotherapy. In this situation 18FDG-PET is helpful in deciding whether or not a residual mass post-chemotherapy contains active tumor. 18FDG-PET can not replace retroperitoneal lymph node dissection for staging purposes.ZusammenfassungDas Ziel dieser 1991 begonnenen prospektiven Studie war, die Bedeutung der Positronenemissionstomographie mit 18FDG bei der Diagnostik der Lymphknotenmetastasen von Hodentumoren zu untersuchen, da zu diesem Zeitpunkt keine Daten bezüglich dieser Fragestellung zur Verfügung standen. Es wird über 54 Patienten berichtet (27 Patienten mit reinem Seminom, 27 Patienten mit nichtseminomatösen Tumoren), bei denen die 18FDG-PET-Resultate mit den Befunden der abdominellen Computertomographie, den Werten für die Tumormarker (AFP, β -HCG) sowie den histopathologischen Befunden nach primärer oder post-chemotherapeutischer retroperitonealer Lymphknotendissektion verglichen wurden. Bei reinen Seminomen im klinischen Stadium I nach der Lugano-Klassifikation (N = 21) waren die 18FDG-PET-Ergebnisse identisch mit denen der Computertomographie, so daß das Verfahren bei dieser Patientengruppe keine zusätzlichen Informationen bringt. Bei Patienten mit nichtseminomatösen Tumoren im Stadium I (N = 7) wurden bei 4 Patienten die vorliegenden Mikrometastasen durch die PET nicht detektiert, bei 1/7 Patienten hat die PET-Messung einen suspekten Herd ergeben, es fanden sich 2 Mikrometastasen in einem zusätzlich entzündlich veränderten Lymphknoten. In 1/7 Fall hat die 18FDG-PET eindeutig Metastasen detektiert (Tumormarker und Computertomogramm waren unauffällig). Bei den reinen Seminomen der Stadien II B und II C (N = 6) hat 18FDG-PET nach Chemotherapie das tumorfreie Lymphknotendissektat (pN0) von den 4 operierten Patienten 3 mal richtig präoperativ erkannt und im vierten Fall einer persistierenden großen Raumforderung die benigne Eigenschaft der Läsion (Ganglioneurom) identifiziert. Computertomographisch wurde dieser Befund als maligne (falsch-positiv) eingestuft, und bei 2/4 Patienten konnten computertomographisch residuale Lymphknoten nach Chemotherapie nicht eindeutig klassifiziert werden. Bei 20 Patienten mit nicht-seminomatösen Tumoren (Stadien II und III) konnte mit 18FDG-PET der Einfluß der Chemotherapie durch Aktivitätsminderung in prätherapeutisch hypermetabolen Herden (Normalisierung bis auf Hintergrundniveau) dargestellt werden. Es gibt eine einzige maligne Ausprägung der Hodentumoren, das reife Teratom, welche keine vermehrte 18FDG-Aufnahme zeigt. Bei computertomographisch erkennbaren, in der PET aber unauffällig dargestellten Läsionen sind differentialdiagnostisch reifes Teratom, Narbengewebe und/oder Nekrose bzw. seltene andere Tumorarten ohne gesteigerten Glukosestoffwechsel in Erwägung zu ziehen, aber eindeutige Unterschiede der Traceraufnahme zur weiteren Differenzierung wurden nicht beobachtet. In 1/20 Fall lag in der PET postchemotherapeutisch ein hypermetaboler Herd, fälschlich als maligne eingestuft, vor, der entsprechende Lymphknoten zeigte histopathologisch entzündliche Veränderungen. 18FDG-PET ist nicht als Routine-Untersuchungsverfahren bei Hodentumoren anzusehen. Die sinnvollste Anwendung ist bei der Bewertung von post-chemotherapeutischen Residualtumoren gegeben, um eine Entscheidungshilfe bei der Indikationsstellung zur RLA/weiteren Chemotherapie zu sein, jedoch ist die RLA zum Staging der Lymphknoten durch den Einsatz der 18FDG-PET nicht zu ersetzen.

Chromophilic renal cell carcinoma: cytomorphological and cytogenetic characterisation of four permanent cell lines.

Chromophilic renal cell carcinoma is a distinct type of human renal cancer, only recently recognised and defined by its characteristic histomorphological aspect and cytogenetic aberrations. We are the first to report on the establishment and cytogenetic characterisation of a panel of four permanent cell lines, i.e. chromphi-1, -2, -3 and -4, derived from strictly defined renal cell carcinomas (RCCs) of the chromophilic type and kept in continuous culture for up to 5 years. Immunohistochemistry revealed coexpression of vimentin and cytokeratins in all cell lines the cytokeratin polypeptide patterns, however, varying between the different cell lines. By light and transmission electron microscopy, various amounts of cytoplasmatic glycogen deposition were observed, being most pronounced in chromphi-3 and -4. The mean population doubling time ranged from 24 h (chromphi-1) to 51 h (chromphi-4). Chromphi-1 tumour cells produced slowly growing tumours in nude mice using the subrenal capsule assay. In all cell lines, cytogenetic analysis revealed numerical chromosomal aberrations known to be characteristic for chromophilic RCCs, i.e. loss of the Y chromosome, tri- or tetrasomy of chromosomes 7 and 17 as well as various combinations of additional structural and numerical chromosomal aberrations. Karyological aberrations were least pronounced in chromphi-2 and most complex in chromphi-1. Chromosomal aberrations typically affecting the short arm of chromosome 3 in clear cell RCCs were not observed in any of our cell lines.