Effect of long-term storage on hormone measurements in samples from pregnant women: the experience of the Finnish Maternity Cohort

Validity of biobank studies on hormone associated cancers depend on the extent the sample preservation is affecting the hormone measurements. We investigated the effect of long-term storage (up to 22 years) on immunoassay measurements of three groups of hormones and associated proteins: sex-steroids [estradiol, progesterone, testosterone, dihydroepiandrosterone sulphate (DHEAS), sex hormone-binding globulin (SHBG)], pregnancy-specific hormones [human chorionic gonadotropin (hCG), placental growth hormone (pGH), alpha-fetoprotein (AFP)], and insulin-like growth factor (IGF) family hormones exploiting the world largest serum bank, the Finnish Maternity Cohort (FMC). Hormones of interest were analyzed in a random sample of 154 Finnish women in the median age (29.5 years, range 25 to 34 years) of their first pregnancy with serum samples drawn during the first trimester. All hormone measurements were performed using commercial enzyme-linked- or radio-immunoassays. Storage time did not correlate with serum levels of testosterone, DHEAS, hCG, pGH and total IGFBP-1. It had a weak or moderate negative correlation with serum levels of progesterone (Spearman's ranked correlation coefficient (r(s))=- 0.36), IGF-I (r(s)=-0.23) and IGF binding protein (BP)-3 (r(s)=-0.38), and weak positive correlation with estradiol (r(s)=0.23), SHBG (r(s)=0.16), AFP (r(s)=0.20) and non-phosphorylated IGF binding protein (BP)-1 (r(s)=0.27). The variation of all hormone levels studied followed the kinetics reported for early pregnancy. Bench-lag time (the time between sample collection and freezing for storage) did not materially affect the serum hormone levels. In conclusion, the stored FMC serum samples can be used to study hormone-disease associations, but close matching for storage time and gestational day are necessary design components of all related biobank studies.

Prognostic impact of carbonic anhydrase IX expression in human renal cell carcinoma

OBJECTIVE

To evaluate the prognostic information of carbonic anhydrase (CA) IX expression in patients with renal cell carcinoma (RCC), as increased expression of CA IX is correlated with a worse prognosis in several malignancies.

PATIENTS AND METHODS

CA IX expression was assessed in RCC tumours from 228 patients, using a tissue microarray technique on archival material. The expression was related to RCC cell type, Tumour-Node-Metastasis (TNM) stage, nuclear grade and survival.

RESULTS

CA IX expression was significantly higher (P < 0.001) in 183 conventional than in 31 papillary RCC and 14 chromophobe RCC. For conventional RCC there was no correlation of CA IX expression with TNM stage or nuclear grade. To evaluate the prognostic information conventional RCC tumours were subdivided arbitrarily into three groups according to the CA IX expression, of 0-10%, 11-90% and 91-100% expression, respectively. Patients with tumours with 0-10% expression had a less favourable prognosis than those with 11-90% and 91-100% expression (P = 0.012, and 0.001), respectively. A multivariate analysis of prognostic factors for patients with conventional RCC showed that TNM stage, nuclear grade and CA IX were independent predictors of prognosis.

CONCLUSION

These results show that CA IX expression is higher in conventional than other RCC cell types; furthermore, patients with conventional RCC with low CA IX expression had a less favourable prognosis.

Evaluation of CD31 (PECAM-1) expression using tissue microarray in patients with renal cell carcinoma

Intratumoural microvessel density (MVD) has prognostic significance in selected neoplasms. To evaluate the prognostic information of MVD in renal cell carcinoma (RCC) we assessed the immunohistochemical expression of CD31 in 208 tumours using the tissue microarray technique. The expression was related to tumour cell type, TNM stage, nuclear grade and survival. CD31 expression was significantly (p < 0.001) higher in 167 conventional RCCs (clear cell) compared to 28 papillary RCCs. In conventional RCC, CD31 expression was inversely correlated to TNM stage (p = 0.024) and nuclear grade (p = 0.010). To evaluate the impact of CD31 expression on tumour-specific survival, the conventional RCC tumours were subdivided into quartiles according to the CD31 expression. In univariate analysis, patients with tumours in the quartile with the highest expression had a more favourable prognosis (p = 0.01) compared to those with lower CD31 expression. A multivariate analysis of prognostic factors in conventional RCC showed that TNM stage and nuclear grade were independent predictors of prognosis, but CD31 expression did not add further prognostic information.

Angiogenesis and other markers for prediction of survival in metastatic renal cell carcinoma

OBJECTIVE

The treatment of metastatic renal cell carcinoma (RCC) remains a clinical challenge. Factors predicting any benefit of different therapies would therefore be useful. Angiogenesis is important in tumor progression and the development of metastases. The aim of this study in patients with distant metastases at diagnosis was to evaluate possible outcome information obtained with a number of soluble angiogenic variables in serum.

MATERIAL AND METHODS

Serum samples were taken at diagnosis from 120 consecutive patients with metastatic RCC who were operated on with radical nephrectomy. Different clinicopathological variables and vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-1 (VEGFR-1), basic fibroblast growth factor (bFGF) and erythropoietin levels in serum were compared with the clinical course.

RESULTS

The median survival time for all patients was 9 months. Six patients (5%) died during the postoperative period, all of whom had a performance status (PS) of 2 or 3. None of the angiogenic factors (VEGF, VEGFR-1, bFGF, erythropoietin) gave any prognostic information, except that VEGF was associated with survival (p = 0.0234) in patients with a good PS. A number of other variables gave prognostic information in univariate analysis but, after multivariate analysis, only PS (p = 0.002), the number of metastatic sites (p = 0.003) and capsule invasion (p = 0.017) remained as independent predictive factors.

CONCLUSIONS

Among predictive factors, only PS, the number of metastatic sites and capsule invasion independently predicted survival in patients with metastatic RCC, while soluble angiogenic factors in serum gave no prognostic information. Nephrectomy in patients with metastatic RCC remains controversial but long-term survival can be achieved in selected patients, especially those with a good PS.

Insulin-like Growth Factor I in Pregnancy and Maternal Risk of Breast Cancer

BACKGROUND

The role of insulin-like growth factor (IGF)-I in breast cancer remains controversial, despite numerous reports on the association of the hormone with breast cancer or high-risk mammographic densities. We hypothesized that exposure to elevated IGF-I during early pregnancy, a period characterized by intense cell proliferation in the breasts and in the presence of high concentrations of sex steroids, will be associated with increased maternal risk to develop a breast malignancy.

METHODS

The Northern Sweden Maternity Cohort is an ongoing prospective study, collecting blood samples from first-trimester-pregnant women since 1975 as part of screening for infectious diseases. A case-control study (212 cases and 369 controls) was nested among Northern Sweden Maternity Cohort members who delivered singleton babies. RIA was used to measure IGF-I and IGF-II levels. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Breast cancer risk increased with increasing IGF-I (top tertile OR, 1.7; 95% CI, 1.1-2.7). The association was stronger among the primiparous (OR, 2.2; 95% CI, 1.1-4.4) than in the nonprimiparous women (OR, 1.4; 95% CI, 0.7-2.8). Upper-tertile risks seemed to decrease within the <28-, 28 to 33, and >33-year groups of age at sampling, from 2.5 (0.9-7.6) to 2.1 (0.9-5.0) and 1.2 (0.5-2.5), respectively. There was no association of breast cancer with first-trimester-pregnancy IGF-II.

CONCLUSIONS

The study offers further evidence that IGF-I is important in breast cancer. Our findings suggest that the adverse effect of IGF-I on the breast may be stronger before the remodeling of the gland induced by a first pregnancy.

Induction of apoptosis by intracellular potassium ion depletion: Using the fluorescent dye PBFI in a 96-well plate method in cultured lung cancer cells

Depletion of intracellular potassium ions (K+) is necessary for cells to shrink, activate caspases and induce DNA fragmentation, events which are features of apoptosis. Here we describe a 96-well plate method using the cell permeable form of K+ binding benzofuran isophtalate (PBFI-AM) to measure intracellular K+ content in relation to untreated control. Cultured human pulmonary mesothelioma cells (P31) and small-cell lung cancer cells (U1690) were treated with K+ flux modulators in order to deprive the cells of intracellular K+. The combination of K+ influx inhibition with 10 micromol/L bumetanide plus 10 micromol/L ouabain and K+ efflux stimulation with 3 mg/L amphotericin B or 5 micromol/L nigericin efficiently reduced the intracellular K+ content after 3 h. Manipulation of K+ fluxes with subsequent intracellular K+ depletion induced apoptosis of lung cancer cells, as detected by caspase-3 activity after 3 h K+ depletion followed by 24 h proliferation and TUNEL positive staining after 48 h proliferation. We concluded that the PBFI-AM assay was a useful tool to determine intracellular K+ content in relation to untreated control, and that intracellular K+ depletion of lung cancer cells by clinically used drugs of relevant concentrations induced apoptosis. These findings may lead to novel therapeutic strategies in the treatment of lung cancer.

Different vascular endothelial growth factor (VEGF), VEGF-receptor 1 and -2 mRNA expression profiles between clear cell and papillary renal cell carcinoma

OBJECTIVES

To examine vascular endothelial growth factor (VEGF), VEGF-receptor-(R)1, and R2 mRNA levels in renal cell carcinoma (RCC), a tumour generally refractory to most medical therapy, but for which a potentially useful therapeutic alternative is inhibition of angiogenesis.

PATIENTS AND METHODS

VEGF, VEGF-R1 and -R2 mRNA levels were analysed using the quantitative reverse transcription-polymerase chain reaction. RNA was extracted from 84 conventional (clear cell) RCCs (cRCC), 20 papillary (pRCC), six chromophobe (chRCC), and 27 corresponding kidney cortex tissues, obtained from 110 patients in whom high-quality RNA was available from the tumours (53 women and 57 men, mean age 64.7 years, range 25-85).

RESULTS

The VEGF, VEGF-R1, and -R2 mRNA levels were higher in tumour than in kidney cortex tissues. Among the RCC types, cRCC had higher VEGF levels than pRCC. In cRCC, VEGF-R2 levels were higher in stage I-II than in more advanced stages. In pRCC, VEGF and VEGF-R2 levels were higher in stage III than in stage I-II tumours. In cRCC, patients with VEGF levels below the median had a significantly shorter survival time than those with higher levels. By contrast, in pRCC, VEGF, VEGF-R1 and -R2 RNA levels above the median were related to adverse survival. Using multivariate analysis in cRCCs, VEGF-R1 mRNA level was the last factor to be omitted after stepwise elimination analysis.

CONCLUSION

VEGF and its receptors were associated with tumour stage and survival, but were not independent prognostic factors. Different RCC types had different expression patterns of VEGF and receptor mRNA levels. We conclude that different pathways might be involved in regulating angiogenesis in the specific RCC types. Detailed knowledge of angiogenesis in RCC is essential when designing new treatment trials where angiogenesis inhibition is used.

Hypoxia-inducible factor 1alpha expression in renal cell carcinoma analyzed by tissue microarray

OBJECTIVES

Angiogenesis is important for tumour progression and metastatic spread. Hypoxia-inducible factor 1alpha (HIF-1alpha) is a major factor regulating a number of other angiogenic factors. Renal cell carcinoma (RCC) is a malignancy with a variable clinical course, partly attributable to specific genetic alterations of the different RCC types. We therefore analysed HIF-1alpha expression using immunohistochemistry and related the results to RCC type and clinicopathologic variables.

MATERIAL AND METHODS

We semiquantitatively analysed HIF-1alpha expression using immunohistological staining of a prepared tissue microarray. There were 216 patients including 176 conventional, 26 papillary, and 14 chromophobe RCCs.

RESULTS

The HIF-1alpha staining was found mainly in the cytoplasm. The tumours were subdivided into HIF-1alpha(LOW) and HIF-1alpha(HIGH) on the basis of staining intensity. HIF-1alpha expression between the RCC types did not differ. Patients with conventional RCC showed a trend (p=0.055) towards a prolonged survival for those with HIF-1alpha(HIGH)-staining versus HIF-1alpha(LOW)-staining tumors. In conventional RCC there were significant differences in HIF-1alpha expression in relation to TNM stage, nuclear grade, and vein invasion. In patients with papillary RCC, difference in HIF-1alpha expression was observed only for nuclear grade.

CONCLUSIONS

We studied HIF-1alpha expression in RCC using tissue microarray. In patients with conventional RCC, HIF-1alpha levels were significantly lower in locally aggressive tumors versus localized tumors, and patients with high HIF-1alpha levels tended to have a better prognosis. There seems to be a diverging regulation of angiogenesis between the different RCC types. Further studies of HIF and angiogenesis in RCC are encouraged.

Acquired neonatal thyroid disease due to TSH receptor antibodies in breast milk

INTRODUCTION

We investigated whether thyroid receptor antibodies (TRAb) could result in transient neonatal thyroid disease by transfer through milk from mothers treated for thyrotoxicosis.

AIM

To analyse whether breast milk content of TRAb in euthyroid mothers with treated thyrotoxicosis resulted in neonatal thyroid disease and whether extended breastfeeding prolonged the neonatal disease.

PATIENTS

We tested three TRAb-positive mothers and the course, treatment and outcome for their offspring with neonatal thyrotoxicosis, and six healthy and two TRAb-negative euthyroid mothers with treated thyrotoxicosis during breastfeeding.

METHOD

TRAb was analysed in serum and breast milk by a radioreceptor assay.

RESULTS

TRAb in serum was detectable in all treated mothers, in one mother during her four pregnancies, resulting in all neonates requiring treatment for thyrotoxicosis. Serum TRAb concentration in neonates decreased continuously with time after birth. Breast milk TRAb was detectable in all cases but not in the controls or in TRAb-negative mothers treated for thyrotoxicosis. The calculated half-life for offspring serum and breast milk TRAb was calculated as approx. 3 weeks and 2 months, respectively.

CONCLUSION

Euthyroid TRAb-positive mothers may cause transient neonatal thyroid disease which seems to be worse and more prolonged during breastfeeding as a consequence of TRAb in breast milk.

Different isoform patterns for vascular endothelial growth factor between clear cell and papillary renal cell carcinoma

OBJECTIVE

To investigate the protein expression of vascular endothelial growth factor (VEGF) isoforms in relation to the clinical course in patients with different renal cell carcinoma (RCC) types, as angiogenesis is essential for tumour growth and metastasis.

PATIENTS AND METHODS

Western blots were assayed of protein extracts from tumour and concomitant kidney cortex samples from 96 patients. The levels of VEGF189, VEGF165, and VEGF121 isoforms were correlated with clinicopathological characteristics and survival.

RESULTS

VEGF189 levels were significantly higher in kidney cortex and chromophobe RCC than in papillary and conventional RCC. In papillary RCCs, VEGF189 levels correlated inversely with tumour stage and tumour size. VEGF165 levels were higher in kidney cortex than in RCC, but there was no difference among the RCC types. VEGF121 expression was associated with less advanced tumour stage in conventional RCC. Using multivariate analysis, VEGF189 remained as an independent prognostic factor for patients with papillary RCC.

CONCLUSIONS

VEGF189 was associated with tumour progression; in papillary RCC, VEGF189 was a significant independent prognostic factor. VEGF protein isoform patterns differed among the specific RCC types. Additional knowledge is essential to design new anti-angiogenic therapies for all RCC types.

Adenylate cyclase toxin from Bordetella pertussis enhances cisplatin-induced apoptosis to lung cancer cells in vitro

The present study examined the possibility to enhance lung cancer cell cytotoxicity and apoptosis of the anticancer drug cisplatin by exposure with adenylate cyclase (AC) toxin from Bordetella pertussis. A malignant mesothelioma cell line (P31) and a small-cell lung cancer cell line (U1690) were exposed to increasing concentrations of cisplatin and AC toxin, alone or in combination. Cytotoxicity was determined by a fluorescein-based assay and apoptosis by flow cytometry quantification of annexin V binding. Caspase-3, -8, and -9 activities were measured by enzyme activity assays. The cytotoxicity of AC toxin was time and dose dependent with an LD50 value at 72 h of 3 and 7 mg/L for P31 cells and U1690 cells, respectively. Cisplatin showed a similar time- and dose-dependent cytotoxicity, which was increased in the presence of a low toxic concentration (1 mg/L) of AC toxin. Furthermore, cisplatin caused a dose-dependent increase of annexin V binding cells of both cell lines after 24-h incubation, which was also enhanced in combination with AC toxin. AC toxin (1 mg/L) increased cisplatin-induced caspase-3, -8, and -9 activities in U1690 cells. Only minor increases of caspase-8 and -9 were noted for P31 cells. The present results, together with the knowledge that bacterial toxins decrease side effects of traditional cancer treatment, suggest a possibility to use them to enhance the therapeutic effect of cancer chemotherapy with reduced clinical adverse effects.

Endoglin (CD105) expression in human renal cell carcinoma

OBJECTIVE

To evaluate the prognostic potential of endoglin (CD105) expression in human renal cell carcinoma (RCC), as endoglin is a cell membrane glycoprotein expressed in tumour-associated vascular endothelium and a marker of angiogenesis; intratumoral microvessel density assessed by endoglin staining has prognostic significance in some neoplasms.

PATIENTS AND METHODS

Tumour samples from 210 patients with RCC (168 conventional), diagnosed between 1982 and 1997, were assessed using the tissue microarray technique with immunohistochemical staining for endoglin. The expression of endoglin was related to clinical variables and survival.

RESULTS

Of the tumours, 75% expressed endoglin, and in conventional RCC the expression was inversely correlated to the Tumour-Node-Metastasis (TNM) stage (P = 0.008) and nuclear grade (P = 0.01). There was no correlation between endoglin expression and gender, age, tumour size or cell type. Patients with conventional RCC and high endoglin expression had a more favourable prognosis than those with tumours with lower expression (P = 0.04). A multivariate analysis of prognostic factors showed that TNM stage and nuclear grade were independent predictors of prognosis. Endoglin expression did not add further prognostic information.

CONCLUSION

These results indicate that endoglin expression is inversely related to stage and grade in RCC, and that it is associated with prognosis.

Gene expression profiling predicts survival in conventional renal cell carcinoma

BACKGROUND

Conventional renal cell carcinoma (cRCC) accounts for most of the deaths due to kidney cancer. Tumor stage, grade, and patient performance status are used currently to predict survival after surgery. Our goal was to identify gene expression features, using comprehensive gene expression profiling, that correlate with survival.

METHODS AND FINDINGS

Gene expression profiles were determined in 177 primary cRCCs using DNA microarrays. Unsupervised hierarchical clustering analysis segregated cRCC into five gene expression subgroups. Expression subgroup was correlated with survival in long-term follow-up and was independent of grade, stage, and performance status. The tumors were then divided evenly into training and test sets that were balanced for grade, stage, performance status, and length of follow-up. A semisupervised learning algorithm (supervised principal components analysis) was applied to identify transcripts whose expression was associated with survival in the training set, and the performance of this gene expression-based survival predictor was assessed using the test set. With this method, we identified 259 genes that accurately predicted disease-specific survival among patients in the independent validation group (p < 0.001). In multivariate analysis, the gene expression predictor was a strong predictor of survival independent of tumor stage, grade, and performance status (p < 0.001).

CONCLUSIONS

cRCC displays molecular heterogeneity and can be separated into gene expression subgroups that correlate with survival after surgery. We have identified a set of 259 genes that predict survival after surgery independent of clinical prognostic factors.

Increased copy number at 3p14 in breast cancer

INTRODUCTION

The present study was conducted to investigate if chromosome band 3p14 is of any pathogenic significance in the malignant process of breast cancer. Genetic studies have implicated a tumour suppressor gene on chromosome arm 3p and we have proposed LRIG1 at 3p14 as a candidate tumour suppressor. The LRIG1 gene encodes an integral membrane protein that counteracts signalling by receptor tyrosine kinases belonging to the ERBB family. LRIG1 mRNA and protein are expressed in many tissues, including breast tissue.

METHODS

In the present report we analysed the LRIG1 gene by fluorescence in situ hybridisation (FISH), LRIG1 mRNA by quantitative RT-PCR, and LRIG1 protein by western blot analysis. Two tumour series were analysed; one series consisted of 19 tumour samples collected between 1987 and 1995 and the other series consisted of 9 tumour samples with corresponding non-neoplastic breast tissues collected consecutively.

RESULTS

The LRIG1 gene showed increased copy number in 11 out of 28 tumours (39%) and only one tumour showed a deletion at this locus. Increased LRIG1 copy number was associated with increased levels of LRIG1 mRNA (two of three tumours) and protein (four of four tumours) in the tumours compared to matched non-neoplastic breast tissue, as assessed by RT-PCR and western blot analysis.

CONCLUSION

The molecular function of LRIG1 as a negative regulator of ERBB receptors questions the biological significance of increased LRIG1 copy number in breast cancer. We propose that a common, but hitherto unrecognised, breast cancer linked gene is located within an amplicon containing the LRIG1 locus at 3p14.3.

Pharmacological modulation of lung cancer cells for potassium ion depletion

BACKGROUND

Depletion of intracellular potassium ions (K+) is necessary for cells to shrink, induce DNA fragmentation and activate caspases, events which are features of apoptosis.

MATERIALS AND METHODS

We used 86Rb+ as a K+ analogue to evaluate the possibility of pharmacologically depleting human pulmonary mesothelioma (P31) and small cell lung cancer (U1690) cells of K+, for future use in studies of apoptosis induction.

RESULTS

The Na+, K+, 2CI(-)-cotransport inhibitor bumetanide transiently inhibited 86Rb+ influx, but when combined with the Na+, K+, ATPase pump inhibitor ouabain there was a marked and lasting (up to 6 h) 86Rb+ influx inhibition. Cellular K+ efflux was augmented by amphotericin B, digitonin and nigericin. Amphotericin B was an effective 86Rb+ efflux stimulator with low cytotoxicity, whereas digitonin caused cell detachment and nigericin increased LDH release in the U1690 cell line, indicating considerable toxicity of the drugs.

CONCLUSION

It is possible to efficiently reduce intracellular K+ by persistent K+ influx inhibition and simultaneous K+ efflux stimulation with clinically available drugs.

The Expression of Hypoxia-Inducible Factor 1α Is a Favorable Independent Prognostic Factor in Renal Cell Carcinoma

Purpose: Renal cell carcinoma (RCC) is the most common malignancy of the kidney composed of specific tumor types. The sporadic conventional RCCs are, in contrast to the other RCC types, characterized by a high rate of von Hippel-Lindau (VHL) mutations and hypermethylation. The majority of these tumors lack functional VHL protein (pVHL) that leads to increased hypoxia-inducible factor 1α (HIF-1α) expression. The pVHL is the physiologic regulator of the activity of HIF-1α by targeting it to the proteasome for degradation under normoxia. Both pVHL and HIF-1α target other genes that are important for cancer survival and proliferation. Expression of HIF-1α has been linked to poor prognosis in different malignancies, although few studies have been done on the relation between HIF-1α and clinical variables in RCC.

Experimental Design: HIF-1α protein expression was analyzed in tumor tissue from 92 patients with RCC. HIF-1α was quantified by Western blot relative to a positive control.

Results: The HIF-1α protein was expressed as two bands which strongly correlated (r = 0.906, P &lt; 0.001); therefore, they were added and the sum evaluated against clinicopathologic variables. There was no association between HIF-1α and gender, stage, grade, tumor size, or vein invasion. Conventional RCCs had significantly higher HIF-1α expression compared with papillary and chromophobe RCCs and kidney cortex. In conventional RCC, HIF-1α was an independent prognostic factor.

Conclusion: HIF-1α levels varied significantly between the different RCC types. In conventional RCC, HIF-1α was an independent prognostic factor. These data indicate that HIF-1α is involved in tumorogenesis and progression of RCC. Evaluation of other HIF target gene products and correlation to angiogenesis seems warranted.

The expression of hypoxia-inducible factor 1alpha is a favorable independent prognostic factor in renal cell carcinoma

PURPOSE

Renal cell carcinoma (RCC) is the most common malignancy of the kidney composed of specific tumor types. The sporadic conventional RCCs are, in contrast to the other RCC types, characterized by a high rate of von Hippel-Lindau (VHL) mutations and hypermethylation. The majority of these tumors lack functional VHL protein (pVHL) that leads to increased hypoxia-inducible factor 1alpha (HIF-1alpha) expression. The pVHL is the physiologic regulator of the activity of HIF-1alpha by targeting it to the proteasome for degradation under normoxia. Both pVHL and HIF-1alpha target other genes that are important for cancer survival and proliferation. Expression of HIF-1alpha has been linked to poor prognosis in different malignancies, although few studies have been done on the relation between HIF-1alpha and clinical variables in RCC.

EXPERIMENTAL DESIGN

HIF-1alpha protein expression was analyzed in tumor tissue from 92 patients with RCC. HIF-1alpha was quantified by Western blot relative to a positive control.

RESULTS

The HIF-1alpha protein was expressed as two bands which strongly correlated (r = 0.906, P < 0.001); therefore, they were added and the sum evaluated against clinicopathologic variables. There was no association between HIF-1alpha and gender, stage, grade, tumor size, or vein invasion. Conventional RCCs had significantly higher HIF-1alpha expression compared with papillary and chromophobe RCCs and kidney cortex. In conventional RCC, HIF-1alpha was an independent prognostic factor.

CONCLUSION

HIF-1alpha levels varied significantly between the different RCC types. In conventional RCC, HIF-1alpha was an independent prognostic factor. These data indicate that HIF-1alpha is involved in tumorogenesis and progression of RCC. Evaluation of other HIF target gene products and correlation to angiogenesis seems warranted.

Parathyroid Hormone-Related Protein and Serum Calcium in Patients with Renal Cell Carcinoma

OBJECTIVE

To evaluate serum parathyroid hormone-related protein (PTHrP) in relation to serum calcium and clinical outcome of patients with renal cell carcinoma.

METHODS

Sera from 243 patients with renal cell carcinoma were collected prior to therapy. Serum PTHrP was analyzed using an immunoradiometric assay. Tumour stage, nuclear grade, corrected serum calcium, and survival were assessed.

RESULTS

Serum PTHrP was detectable in 37/243 sera (15%) and hypercalcaemia (> or =2.60 mmol/l) in 32/220 (15%). A positive correlation between serum PTHrP and serum calcium was found (r = 0.326; p < 0.01). Following subdivision of the material, based on storage time, the frequency of detectable serum PTHrP seemed to decrease with time. Serum calcium, but not serum PTHrP, was correlated to tumour stage (p < 0.001). Survival was similar for patients with detectable and undetectable PTHrP, but those with hypercalcaemia had a significantly shorter survival time compared to those with normal serum calcium (p < 0.001). A multivariate analysis showed that tumour stage and serum calcium were independent prognostic factors, but not grade or PTHrP.

CONCLUSIONS

A positive relation of serum PTHrP to serum calcium was demonstrated in patients with renal cell carcinoma. Hypercalcaemia but not serum PTHrP predicted a worse prognosis.