ErbB 1-4 expression alterations in primary colorectal cancers and their corresponding metastases

BACKGROUND

EGFR (epidermal growth factor receptor) targeted therapies are important new tools in colorectal cancer treatment. EGFR analysis of the primary tumour was previously recommended to identify patients who will benefit from the EGFR targeted therapy. Previous studies have displayed diverging results regarding the expression of EGFR in the primary tumour compared to the metastases. The present study was performed to investigate whether EGFR and ErbB2-4 expression differed between 64 primary tumours and their corresponding metastases.

PATIENTS AND METHODS

EGFR and ErbB2-4 expression were analysed in the primary tumour and in the corresponding metastases using immunohistochemistry (IHC).

RESULTS

In 49/64 samples (76%), the primary tumours were EGFR positive; in 33% (16/49) of EGFR positive samples, the tumours lost the EGFR expression in the metastasis compared to the primary tumour. From the primary tumours, 15/64 (23%) were negative and 5 of these (33%) developed EGFR expression in the metastasis. ErbB2, ErbB3, and ErbB4 expression was evident in 54%, 67%, and 81%, respectively. There was no significant difference between ErbB2, ErbB3, and ErbB4 expression in primary tumours and metastases. The co-expression of the ErbB family members was also analysed, with a significant increase of ErbB3/ErbB4 co-expression in late stage tumours.

CONCLUSION

The EGFR expression was lost in 33% of metastasising primary colorectal cancer tumours, a finding that agrees with at least one previous study. Thus, the present results clearly implicate the need for EGFR analysis of both the primary tumour and metastases to accurately determine EGFR status when considering the use of EGFR targeted therapies.

Functional polymorphisms in folate metabolism genes influence the risk of meningioma and glioma

Folate metabolism plays an important role in carcinogenesis. To test the hypothesis that polymorphic variation in the folate metabolism genes 5,10-methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) influences the risk of primary brain tumors, we genotyped 1,005 glioma cases, 631 meningioma cases, and 1,101 controls for the MTHFR C677A and A1298C, MTRR A66G, and MTR A2756G variants. MTHFR C677T-A1298C diplotypes were associated with risk of meningioma (P = 0.002) and glioma (P = 0.02); risks were increased with genotypes associated with reduced MTHFR activity. The highest risk of meningioma was associated with heterozygosity for both MTHFR variants [odds ratio (OR), 2.11; 95% confidence interval (95% CI), 1.42-3.12]. The corresponding OR for glioma was 1.23 (95% CI, 0.91-1.66). A significant association between risk of meningioma and homozygosity for MTRR 66G was also observed (OR, 1.41; 95% CI, 1.02-1.94). Our findings provide support for the role of folate metabolism in the development of primary brain tumors. In particular, genotypes associated with increased 5,10-methylenetetrahydrofolate levels are associated with elevated risk.

Acquisition of cisplatin-resistance in malignant mesothelioma cells abrogates Na+,K+,2Cl(-)-cotransport activity and cisplatin-induced early membrane blebbing

AIMS

Resistance mechanisms are important limiting factors in the treatment of solid malignancies with cis-diamminedichloroplatinum(II) (cisplatin). To gain further understanding of the effects of acquired cisplatin-resistance, we compared a human malignant pleural mesothelioma cell line (p31) to a sub-line (p31res1.2) with acquired cisplatin-resistance.

METHODS AND RESULTS

The role of Na(+),K(+),2Cl(-)-cotransport (NKCC1) activity in cisplatin-induced morphological changes and acquired cisplatin-resistance was investigated in a time-resolved manner. Acquisition of cisplatin-resistance resulted in markedly reduced NKCC1 activity, absence of cisplatin-induced early membrane blebbing, and increased basal caspase-3 activity. At equitoxic cisplatin concentrations, P31res1.2 cells had a faster activation of caspase-3 than P31 cells, but the end-stage cytotoxicity and number of cells with DNA fragmentation was similar. Bumetanide inhibition of NKCC1 activity in P31 cells repressed cisplatin-induced early-phase membrane blebbing but did not increase P31 cell resistance to cisplatin.

CONCLUSIONS

Together, these results suggest that active NKCC1 was necessary for cisplatin-induced early membrane blebbing of P31 cells, but not for cisplatin-resistance. Thus, acquisition of cisplatin-resistance can affect mechanisms that have profound effects on cisplatin-induced morphological changes but are not necessary for the subsequent progression to apoptosis.

The common D302H variant of CASP8 is associated with risk of glioma

Caspase 8 (CASP8) is a key regulator of apoptosis or programmed cell death, and, hence, a defense against cancer. We tested the hypothesis that the CASP8 polymorphism D302H influences risk of glioma through analysis of five series of glioma case patients and controls (n = 1,005 and 1,011, respectively). Carrier status for the rare allele of D302H was associated with a 1.37-fold increased risk (95% confidence interval, 1.10-1.70; P = 0.004). The association of CASP8 D302H with glioma risk indicates the importance of inherited variation in the apoptosis pathway in susceptibility to this form of primary brain tumor.

Significant cytotoxic activity in vitro of the EGFR tyrosine kinase inhibitor gefitinib in acute myeloblastic leukaemia

OBJECTIVES

Gefitinib inhibits epidermal growth factor receptor (EGFR) signalling, but may also act by non-EGFR dependent mechanisms. We have investigated the activity of gefitinib in haematological tumour cells, in particular acute myeloblastic leukaemia (AML).

METHODS

Cytotoxic activity of gefitinib, alone or in combination with standard anti-leukaemic drugs, was assessed by the short-term fluorometric microculture cytotoxicity assay in tumour cells from 117 patients representing five haematological and five non-haematological malignancies. In AML, the EGFR status was analysed by immunochemistry. Gefitinib-induced apoptosis was investigated in a subset of AML samples, as well as in the leukaemia cell line MV-4-11, using a multiparametric high content screening assay. To confirm activation of caspase-3 in cells treated with gefitinib, a blocking test was carried out in which MV4-11 cells were pretreated with the specific caspase inhibitor DEVD-FMK.

RESULTS

Gefitinib showed highest cytotoxic activity in AML (n = 19) with many samples being sensitive at concentrations achievable in clinical practice (<10 microM), and no difference between previously untreated and relapsed patients. No correlation between the activity of gefitinib and standard antileukaemic drugs (cytarabine, doxorubicin, etoposide) was observed. Combining gefitinib with these drugs resulted in mainly additive or synergistic (etoposide) effects, with no evidence of sequence dependency. The AML cells did not express the EGFR. Gefitinib induced apoptosis, which was at least partly mediated by activation of the caspase-3 pathway.

CONCLUSION

In vitro, gefitinib has significant cytotoxic activity in AML by inducing apoptosis through non-EGFR dependent pathways.

Glucose metabolites, glutamate and glycerol in malignant glioma tumours during radiotherapy

OBJECTIVE

The metabolism of malignant glioma was studied in 13 patients. The main objective was to perform a study of the metabolic pattern of glucose, lactate, pyruvate, glutamate and glycerol in tumour tissue during base-line conditions and to detect any changes in the metabolism during radiotherapy.

METHOD

During a stereotactic biopsy, two microdialysis catheters were implanted: one in tumour and one in peri-tumoural tissue. Fasting samples were analysed daily, before and during 5 days of radiotherapy given with 2 Gy fractions.

RESULTS

Base-line levels of glucose and pyruvate were significantly lower in tumour compared to peri-tumoural tissue (P = 0.04 and 0.023, respectively). The lactate/pyruvate ratio was significantly higher in tumour tissue (P = 0.022). In general, the levels of lactate, glutamate and glycerol were higher in tumour tissue, although not statistically significant. Further, we could not detect any significant changes during the 5 days of radiotherapy in any of the metabolites analysed.

CONCLUSION

Radiotherapy up to 10 Gy given in five fractions does not influence the glucose metabolism nor does it induce any acute cytotoxic effect detected with glutamate or glycerol in malignant glioma, as assessed by microdialysis. The study confirms the glycolytic properties of glucose metabolism in malignant glioma.

Polymorphisms in predicted microRNA-binding sites in integrin genes and breast cancer: ITGB4 as prognostic marker

Integrins control the cell attachment to the extracellular matrix and play an important role in mediating cell proliferation, migration and survival. A number of important cancer-associated integrin genes can be regulated by microRNAs (miRNAs) that bind to their target sites in the 3' untranslated regions. We examined the effect of single-nucleotide polymorphisms (SNPs) in predicted miRNA target sites of six integrin genes (ITGA3, ITGA6, ITGAv, ITGB3, ITGB4 and ITGB5) on breast cancer (BC) risk and clinical outcome. Six SNPs were genotyped in 749 Swedish incident BC cases with detailed clinical data and up to 15 years of follow-up together with 1493 matched controls. We evaluated associations between genotypes and BC risk and clinical tumour characteristics. Survival probabilities were compared between different subgroups. As a novel finding, several SNPs seemed to associate with the hormone receptor status. The strongest association was observed between the A allele of the SNP rs743554 in the ITGB4 gene and oestrogen receptor-negative tumours [odds ratio 2.09, 95% confidence intervals (CIs) 1.19-3.67]. The same SNP was associated with survival. The A allele carriers had a worse survival compared with the wild-type genotype carriers (hazard ratio 2.11, 95% CIs 1.21-3.68). The poor survival was significantly associated with the aggressive tumour characteristics: high grade, lymph node metastasis and high stage. None of the SNPs was significantly associated with BC risk. As the ITGB4 SNP seems to influence tumour aggressiveness and survival, it may have prognostic value in the clinic.

Reproducibility and geometric accuracy of the Fixster system during hypofractionated stereotactic radiotherapy

Background

Hypofractionated radiotherapy has been used for the treatment of AVMs and brain metastases. Hypofractionation necessitates the use of a relocatable stereotactic frame that has to be applied on several occasions. The stereotactic frame needs to have a high degree of reproducibility, and patient positioning is crucial to achieve a high accuracy of the treatment.

Methods

In this study we have, by radiological means, evaluated the reproducibility of the isocenter in consecutive treatment sessions using the Fixster frame. Deviations in the X, Y and Z-axis were measured in 10 patients treated with hypofractionated radiotherapy.

Results

The mean deviation in the X-axis was 0.4 mm (range -2.1 – 2.1, median 0.7 mm) and in the Y-axis -0.3 mm (range -1.4 – 0.7, median -0.2 mm). The mean deviation in the Z-axis was -0.6 (range -1.4 – 1.4, median 0.0 mm).

Conclusion

There is a high degree of reproducibility of the isocenter during successive treatment sessions with HCSRT using the Fixster frame for stereotactic targeting. The high reducibility enables a safe treatment using hypofractionated stereotactic radiotherapy.

An international case-control study of interleukin-4Ralpha, interleukin-13, and cyclooxygenase-2 polymorphisms and glioblastoma risk

Previous studies found that allergies are inversely related to risk of glioma. In an earlier publication, using data from a Swedish case-control study, Schwartzbaum et al. report an inverse relation between risk of glioblastoma and four single nucleotide polymorphisms (SNP) on two genes [interleukin (IL)-4Ralpha, IL-13] that are associated with allergies. In addition, recent studies suggest that IL-4 and IL-13 induce cyclooxygenase-2 (COX-2) to resolve brain inflammation. To see whether previous Swedish results (110 cases, 430 controls) would be replicated, we estimated the association between glioblastoma and two IL-4Ralpha (rs1805015, rs1801275) and two IL-13 (rs20541, rs1800925) SNPs and their haplotypes and one COX-2 SNP (-765GC) using additional English, Danish, and Finnish data (217 cases, 1,171 controls). Among general population controls, we evaluated associations between these haplotypes, the COX-2 SNP, and self-reported allergies. Our data did not support our original observations relating individual IL-4Ralpha, IL-13, or COX-2 SNPs to glioblastoma risk. However, the T-G IL-4Ralpha haplotype was associated with glioblastoma risk (odds ratio, 2.26; 95% confidence interval, 1.13-4.52) and there was a suggestion of an inverse relation between this haplotype and hayfever prevalence among controls (odds ratio, 0.38; 95% confidence interval, 0.14-1.03). The lack of support for a link between four IL-4Ralpha and IL-13 SNPs and glioblastoma may reflect the absence of associations or may result from uncontrolled confounding by haplotypes related both to those that we examined and glioblastoma. Nonetheless, the association between the T-G IL-4Ralpha haplotype and glioblastoma risk may indicate a role of immune factors in glioblastoma development.

Breast cancer survival is associated with telomere length in peripheral blood cells

Telomeres are essential for maintaining chromosomal stability. Previous studies have indicated that individuals with shorter blood telomeres may be at higher risk of developing various types of cancer, such as in lung, bladder, and kidney. We have analyzed relative telomere length (RTL) of peripheral blood cells in relation to breast cancer incidence and prognosis. The study included 265 newly diagnosed breast cancer patients and 446 female controls. RTL was measured by real-time PCR, and our results show that the patient group displayed significantly longer telomeres compared with controls (P < 0.001). Age-adjusted odds ratios (OR) for breast cancer risk increased with increasing telomere length, with a maximal OR of 5.17 [95% confidence interval (95% CI), 3.09-8.64] for the quartile with the longest telomeres. Furthermore, RTL carried prognostic information for patients with advanced disease. Node positive (N+) patients with short telomeres (</=median) showed an increased survival compared with N+ patients with long telomeres (P = 0.001). For patients with ages <50 years with tumors >16 mm (median tumor diameter), short telomeres were associated with a significantly better outcome than longer telomeres (P = 0.006). Cox regression analysis showed that long RTL was a significant independent negative prognostic factor (hazards ratio, 2.92; 95% CI, 1.33-6.39; P = 0.007). Our results indicate that blood RTL may serve as a prognostic indicator in breast cancer patients with advanced disease.

Mammaglobin and lipophilin B expression in breast tumors and their lack of effect on breast cancer cell proliferation

BACKGROUND

Mammaglobin (SCGB2A2) and lipophilin B (SCGB1D2) are members of the secretoglobin polypeptide family. Mammaglobin has been shown to be overexpressed in breast tumor tissue, indicating that mammaglobin might confer a growth advantage to mammaglobin-expressing tumor cells.

MATERIALS AND METHODS

The mammaglobin and lipophilin B mRNA expression levels were investigated in seven breast tumors and matched nonneoplastic tissues from the same patients using quantitative real-time RT-PCR. The effect of mammaglobin and lipophilin B expression on breast cancer cell proliferation rates was investigated by analyzing retrovirally transduced Hs578T cell clones. Cell proliferation rates were determined during the exponential growth phase by analyzing the change in lactate dehydrogenase activity over time.

RESULTS

All analyzed breast cancer tumors had lower expression levels of mammaglobin and lipophilin B than the respective mean level of the nonneoplastic breast tissues; no prominent overexpression was evident. There was high variability in the expression of mammaglobin and lipophilin B among the non-neoplastic samples, showing that caution should be taken when evaluating their over- and underexpression in tumors. The expression levels of mammaglobin and lipophilin B correlated with each other in the analyzed samples (p = 0.001). Ectopic overexpression of mammaglobin and lipophilin B did not affect the cell proliferation rate of Hs578T breast carcinoma cells in vitro.

CONCLUSION

Our findings suggest that the overexpression of mammaglobin observed in certain breast tumors is an epiphenomenon not causally involved in breast carcinogenesis.

LRIG1 expression in colorectal cancer

In the present study the expression of LRIG1 (leucine rich repeats and immunoglobin-like domains 1) and its relation to EGFR (epidermal growth factor receptor) was examined in tumour samples and adjacent non-neoplastic tissues from 30 patients with colorectal cancer. The LRIG1 gene, at chromosome 3p14, encodes an intergral membrane protein, which counteracts signalling by receptor tyrosine kinases belonging to the ERBB (epidermal growth factor receptor) family. LRIG1 is expressed in all tissues and organs analysed to date, including breast, brain, skin, kidney, spleen and colon. Overexpression of EGFR is seen in 70 - 90% of colorectal cancers, and is associated with a poor survival. Western blot analysis showed LRIG1 upregulation in 43% and downregulation in 43% of the colorectal cancers compared to adjacent non-neoplastic tissue. No correlation was evident between LRIG1, analysed by Western Blot and the expression of EGFR analysed by immunohistochemistry. FISH (fluoroscence in situ hybridisAtion) analysis showed increased LRIG1 copy number in one of nine tumours. Four colorectal cancer cell lines demonstrated two LRIG1 gene copies. In conclusion, there was a great heterogeneity in the expression of the LRIG1 protein in colorectal cancer, which was not related to gene dosage of the LRIG1 gene. Further studies can be of interest to evaluate whether alteration in LRIG1 expression in colorectal cancer is of biological or clinical significance.

Comprehensive analysis of DNA repair gene variants and risk of meningioma

BACKGROUND

Meningiomas account for up to 37% of all primary brain tumors. Genetic susceptibility to meningioma is well established, with the risk among relatives of meningioma patients being approximately threefold higher than that in the general population. A relationship between risk of meningioma and exposure to ionizing radiation is also well known and led us to examine whether variants in DNA repair genes contribute to disease susceptibility.

METHODS

We analyzed 1127 tagging single-nucleotide polymorphisms (SNPs) that were selected to capture most of the common variation in 136 DNA repair genes in five case-control series (631 case patients and 637 control subjects) from four countries in Europe. We also analyzed 388 putative functional SNPs in these genes for their association with meningioma. All statistical tests were two-sided.

RESULTS

The SNP rs4968451, which maps to intron 4 of the gene that encodes breast cancer susceptibility gene 1-interacting protein 1, was consistently associated with an increased risk of developing meningioma. Across the five studies, the association was highly statistically significant (trend odds ratio = 1.57, 95% confidence interval = 1.28 to 1.93; P(trend) = 8.95 x 10(-6); P = .009 after adjusting for multiple testing).

CONCLUSIONS

We have identified a novel association between rs4968451 and meningioma risk. Because approximately 28% of the European population are carriers of at-risk genotypes for rs4968451, the variant is likely to make a substantial contribution to the development of meningioma.

Comprehensive analysis of the role of DNA repair gene polymorphisms on risk of glioma

Much of the variation in inherited risk of glioma is likely to be explained by combinations of common low risk variants. The established relationship between glioma risk and exposure to ionizing radiation led us to examine whether variants in the DNA repair genes contribute to disease susceptibility. We evaluated 1127 haplotype-tagging single-nucleotide polymorphisms (SNPs) supplemented with 388 putative functional SNPs to capture most of the common variation in 136 DNA repair genes, in five unique case-control series from four different countries (1013 cases, 1016 controls). We identified 16 SNPs associated with glioma risk at the 1% significance level. The highest association observed across the five independent case-control datasets involved rs243356, which maps to intron 3 of CHAF1A (trend odds ratio, 1.32; 95% confidence interval 1.14-1.54; P = 0.0002; false-positive report probability = 0.055, based on a prior probability of 0.01). Our results provide additional support for the hypothesis that low penetrance variants contribute to the risk of developing glioma and suggest that a genetic variant located in or around the CHAF1A gene contributes to disease risk.

Redistribution of LRIG proteins in psoriasis

The human leucine-rich repeats and immunoglobulin-like domains (LRIG) family is composed of three members, LRIG1, -2, and -3, which are all expressed in human skin. LRIG1 negatively regulates growth factor signaling and is involved in the regulation of epidermal stem cell quiescence. Ablation of Lrig1 in mice results in psoriasiform epidermal hyperplasia. Hence, the LRIG proteins may be important for epidermal homeostasis and in psoriasis. Therefore, we analyzed the LRIG mRNA levels and the cellular and subcellular distribution of LRIG proteins in normal and psoriatic skin. The mRNA levels of LRIG1, -2, and -3 were not significantly different in psoriatic epidermis compared to clinically normal epidermis from the same patient. Immunohistochemistry showed that all three LRIG proteins were expressed in unique and specific patterns both in normal and psoriatic skin. Intriguingly, in psoriatic epidermis, the LRIG protein expression patterns were altered compared to normal skin. These results indicate that the LRIG proteins may have a role in epidermal homeostasis and psoriasis.

Clinical value of using serological cytokeratins as therapeutic markers in thoracic malignancies

In recent years, there has been an increasing awareness among physicians of the value of therapeutic interventions in patients suffering from lung cancer and mesothelioma. A search for an optimal approach using surgery, irradiation and chemotherapy in different settings of the tumour disease, including curatively aimed adjuvant chemotherapy after locoregional surgery or radiotherapy, has resulted in gradually improved survival rates. Still, early detection is crucial if there is to be a possibility of curing patients or prolonging life in cases of relapsed disease. Several studies have been initiated in which surrogate markers are evaluated in comparison to chest X-rays and computer tomography. The present review focuses on the predictive and prognostic value of using serological cytokeratins as tumour markers for patients suffering from thoracic malignancies.

LRIG1 and squamous epithelial uterine cervical cancer: correlation to prognosis, other tumor markers, sex steroid hormones, and smoking

The aim is to evaluate LRIG1 as a prognosis predictor and correlations to cofactors in squamous cell cervical cancer. LRIG1 expression was studied in 128 cervical carcinomas and was compared with expression of nine other tumor markers. Smoking history was registered and pretreatment serum estradiol and progesterone levels were evaluated in 79 women. At clinical stage IB, 58% of the tumors showed LRIG1 expression, but there was a decline by increasing stage (33% in stage IV). Ninety percent of women with stage IB cancer and LRIG1 positivity survived, as compared to 64% without expression (P = 0.02). LRIG1 expression did not predict prognosis in advanced stages, but in stage IIA there was a marked relative difference, with 75% survival in tumors expressing LRIG1, as compared to 43% in those without. No correlation was found between LRIG1 and the other nine tumor markers studied. A high serum progesterone and smoking correlated to absent LRIG1 expression. We conclude that LRIG1 appears to be a significant prognosis predictor in early-stage cervical cancer, independent of the other tumor markers that were studied. Diminished expression in advanced stages and the inverse correlation to serum progesterone and smoking indicates that LRIG1 is a tumor suppressor in cervix.