Differing deregulation of EGFR and downstream proteins in primary colorectal cancer and related metastatic sites may be clinically relevant

Cetuximab and panitumumab efficacy in metastatic colorectal cancer (mCRC) may be influenced by EGFR gene status and/or deregulation of its downstream signalling proteins detected in primary tumour. However, metastasis might have different molecular patterns with respect to primary tumour, possibly affecting the prediction of EGFR-targeted therapy efficacy. We analysed primary tumour and metastasis in 38 mCRC patients. Twelve cases were cetuximab/panitumumab treated. EGFR gene status and protein expression were investigated through fluorescent in situ hybridisation and immunohistochemistry (IHC), K-Ras/BRAF mutations by sequencing and PTEN expression by IHC. We observed EGFR gene deregulation in 25 out of 36 primary tumours and 29 out of 36 metastases, K-Ras mutations in 16 out of 37 cancers and in 15 out of 37 metastases, BRAF mutations in 2 out of 36 cancers and 2 out of 36 metastases and PTEN loss in 8 out of 38 cancers and 12 out of 38 metastases. For the first time in literature, we show that primary colorectal cancer and paired metastasis may exhibit difference with respect to EGFR pathway deregulation mechanisms possibly implying a different response to cetuximab or panitumumab treatment. The investigation of treated patients confirms this hypothesis. We therefore suggest that the analysis of metastatic lesion should be considered in patient management as well as in designing future clinical trials aimed to investigate the effect of anti-EGFR monoclonal antibodies in the treatment of mCRC.

Breast cancer classification according to immunohistochemical markers: clinicopathologic features and short-term survival analysis in a population-based study from the South of Switzerland

BACKGROUND

Breast cancer may be classified into distinct molecular subtypes based on gene expression profiling and/or immunophenotypic characteristics. Aim of the study was to investigate prevalence, clinicopathologic features and overall survival (OS) of molecular subtypes, in a large European population-based study.

PATIENTS AND METHODS

All invasive breast cancers from 2003 to 2007 were selected from the files of Ticino Cancer Registry. Molecular subtypes were defined by immunohistochemical markers. Clinicopathological characteristics and short-term OS were analyzed.

RESULTS

Of 1214 invasive breast cancers, 73.2% were luminal A subtype, 13.8% luminal B, 7.4% basal like and 5.6% Her2/neu. Basal like presented largely in premenopausal women and displayed aggressive features, such as large tumor size, poorly differentiated cancers, high Ki-67 proliferation index and the worst 24-month OS. Luminal A included the highest percentage of patients >70, the highest proportion of stage I tumors and well/moderately differentiated lesions. Her2/neu was more frequent in postmenopausal women and showed the highest percentage of positive lymph nodes and stage IV cases.

CONCLUSION

This is a comprehensive European population-based study on breast cancer molecular subtypes. We provide strong evidence that the molecular classification is useful for clinical management and superior to World Health Organization classification in terms of short-term prognostic value.

Kaposi sarcoma incidence in the Swiss HIV Cohort Study before and after highly active antiretroviral therapy

Between 1984 and 2006, 12 959 people with HIV/AIDS (PWHA) in the Swiss HIV Cohort Study contributed a total of 73 412 person-years (py) of follow-up, 35 551 of which derived from PWHA treated with highly active antiretroviral therapy (HAART). Five hundred and ninety-seven incident Kaposi sarcoma (KS) cases were identified of whom 52 were among HAART users. Cox regression was used to estimate hazard ratios (HR) and corresponding 95% confidence intervals (CI). Kaposi sarcoma incidence fell abruptly in 1996-1998 to reach a plateau at 1.4 per 1000 py afterwards. Men having sex with men and birth in Africa or the Middle East were associated with KS in both non-users and users of HAART but the risk pattern by CD4 cell count differed. Only very low CD4 cell count (<50 cells microl(-1)) at enrollment or at HAART initiation were significantly associated with KS among HAART users. The HR for KS declined steeply in the first months after HAART initiation and continued to be low 7-10 years afterwards (HR, 0.06; 95% CI, 0.02-0.17). Thirty-three out of 52 (63.5%) KS cases among HAART users arose among PWHA who had stopped treatment or used HAART for less than 6 months.

Clinical features and new molecular findings in Carnitine Palmitoyltransferase II (CPT II) deficiency

Carnitine palmitoyltransferase II (CPT II) deficiency is the most common inherited disorder of lipid metabolism characterized in its adult form by attacks of myalgia and myoglobinuria. We analyzed a cohort of 22 CPT II-deficient patients (representing 20 independent probands) to correlate clinical presentation and molecular data. The common p.Ser113Leu mutation was detected with an allelic frequency of 67.5% (27/40), in association with mild adult-onset phenotype. In addition to the p.Ser113Leu mutation, other 10 disease-causing mutations were identified, 5 of which were novel. They are a micro-insertion within exon 5, three aminoacid substitutions within the coding region, namely p.Arg151Trp, p.Asp576Gly, p.Arg247Trp and a truncating stop codon mutation (p.Arg554Ter). Our data expand the spectrum of CPT II mutations and help to evaluate possible correlations between genotypes and phenotypes.

Detailed site distribution of melanoma and sunlight exposure: aetiological patterns from a Swiss series

BACKGROUND

The relation between detailed cutaneous distribution of melanoma and indicators of sun exposure patterns has scantily been explored in moderately sun-sensitive populations.

PATIENTS AND METHODS

The precise site of 1658 primary malignant melanoma, registered from 1995 to 2002, in Switzerland were retrieved and clinically validated. Relative melanoma density (RMD) was computed by the ratio of observed to expected number of melanoma allowing for body site surface areas, and further adjusted for site-specific melanocyte density.

RESULTS

Sites of highest risks were the face, shoulder and upper arm for both sexes, the back for men, and leg for women. Major features of this series were: (i) an unexpectedly high RMD for the face in women (5.6 versus 3.7 in men), (ii) the absence of a male predominance for melanoma on the ears and (iii) for the upper limbs, a steady gradient of increasing melanoma density with increasing proximity to the trunk, regardless of sex. Age and sex patterns of RMD parallelled general indicators of sun exposure and behaviour, except for the hand (RMD = 0.2).

CONCLUSION

RMD increased with (cumulative) site sun exposure, but a few notable exceptions support the impact of intermittent exposure in melanoma risk.

Variation in survival after diagnosis of breast cancer in Switzerland

BACKGROUND

Survival after diagnosis of cancer is a key criterion for cancer control. Major survival differences between time periods and countries have been reported by the EUROCARE studies. We investigated whether similar differences by period and region existed in Switzerland.

METHODS

Survival of 11,376 cases of primary invasive female breast cancer diagnosed between 1988 and 1997 and registered in seven Swiss cancer registries covering a population of 3.5 million was analysed.

RESULTS

Comparing the two periods 1988-1992 and 1993-1997, age-standardized 5 year relative survival improved globally from 77% to 81%. Furthermore, multivariate analysis adjusting for age, tumour size and nodal involvement identified regional survival differences. Survival was lowest in the rural parts of German-speaking eastern Switzerland and highest in urbanised regions of the Latin- and German-speaking northwestern parts of the country.

CONCLUSIONS

This study confirms that survival differences are present even in a small and affluent, but culturally diverse, country like Switzerland, raising the issue of heterogeneity in access to care and quality of treatment.

Green tea modulation of inducible nitric oxide synthase in hypoxic/reoxygenated cardiomyocytes

Hypoxia/reoxygenation (H/R) is one of the causes of the increased expression of inducible nitric oxide synthase (iNOS) in cardiomyocytes. Since an aberrant NOS induction has detrimental consequences, we evaluated the effect of a green tea extract (GTE) on the NOS induction and activity in H/R-cardiomyocytes to define a nutritional strategy. Cultured rat cardiomyocytes were exposed to H/R in the presence of two concentrations of a green tea extract (GTE), which is reported to inhibit NOS expression and activity in different cells. In cultured cardiomyocytes two NOS isoforms were constitutively expressed, but only iNOS was induced by H/R. GTE supplementation at the lowest concentration, comparable to that in human plasma after dietary consumption, was ineffective, while the highest, comparable to that achievable by dietary supplements, counteracted the effect of H/R on iNOS induction and activity. It is necessary to verify in humans the relationship between the modulation of NO production and green tea dietary consumption.

Correlation between dietary polyunsaturated fatty acids and plasma homocysteine concentration in vitamin B6-deficient rats

BACKGROUND AND AIM

Vitamin B6 as cofactor of Delta6 desaturase is involved in polyunsaturated fatty acid metabolism; moreover, it is a cofactor of the trans-sulfuration pathway of homocysteine. Some studies report that low concentrations of pyridoxine, by increasing homocysteine levels, are associated with coronary artery disease, and carotid and arterial lesions. The aim of this study was to verify whether different dietary amounts of polyunsaturated fatty acids associated with low content of vitamin B6 could modulate homocysteinemia.

METHODS AND RESULTS

Thirty-two rats were divided into two groups, one fed a diet with adequate vitamin B6 content the other a diet containing low amount of the same vitamin. Within each group, rats were divided into two subgroups differing in the polyunsaturated fatty acid content of the diet (63 and 33%, respectively). The vitamin B6-deficient diet induced an increase in homocysteine concentration compared to the vitamin B6-normal diet. This increase was tenfold in the subgroup fed high polyunsaturated fatty acid levels and twofold in the other subgroup. The fatty acid composition of liver phospholipids showed a lower arachidonic acid relative molar content and a lower 20:4/18:2 ratio in vitamin B6-deficient groups compared with B6-normal groups.

CONCLUSIONS

On the basis of the different biological functions of pyridoxine and considering that some factors closely related to atherosclerosis are vitamin B(6) dependent, adequate pyridoxine availability could be necessary to assure a normal long chain fatty acid metabolism and to reduce the risk linked to hyperhomocysteinemia.

Neuronal differentiation of murine bone marrow Thy-1- and Sca-1-positive cells

Recent evidence suggests that cells from bone marrow can acquire neuroectodermal phenotypes in cell culture or after transplantation in animal models and in the human brain. However, isolation of the bone marrow cell subpopulation with neuronal differentiation potential remains a challenge. To isolate and expand neural progenitors from whole murine bone marrow, bone marrow was obtained from hind limb bone of C57BL6 mice and plated in culture with neuronal medium with basic fibroblast growth factor and epidermal growth factor. After 5-7 days in culture, cellular spheres similar to brain neurospheres appeared either floating or attached to culture dishes. These spheres were collected, dissociated, and expanded. The bone marrow-derived spheres were positive for nestin as assessed by immunocytochemistry and by reverse transcriptase polymerase chain reaction. Thy-1- and Sca-1-positive bone marrow cells selected by magnetic cell sorting resulted in a higher yield of nestin-positive spheres. After exposure to neuronal differentiative medium retinoic acid with and without Sonic hedgehog, cells positive for neuronal markers tubulin III (TuJ-1) and neurofilament (NF) were detected. The mRNA profile of these cells included the expression of TuJ-1, neuronal-specific enolase (NSE), and NF-light chain. To evaluate the in vivo behavior of these cells, spheres derived from bone marrow-derived cells of transgenic green fluorescent protein (GFP) mice were transplanted into newborn mouse brain. Two months later, the mouse neural cortex contained a minor proportion of GFP(+) cells co-expressing neuronal markers (TuJ-1, NF, MAP-2, NeuN). Although cell fusion phenomena with the host cells could not be ruled out, bone marrow-derived neurosphere transplantation could be a strategy for cellular mediated gene therapy.

Remarkable infidelity of polymerase A associated with mutations in POLG1 exonuclease domain

OBJECTIVE

To better understand the still unknown pathologic mechanism involved in the accumulation of multiple mtDNA deletions in stable tissues.

METHODS

A large-scale screening of mtDNA molecules from skeletal muscle was performed in 14 patients with progressive external ophthalmoplegia (PEO) and 2 patients with mitochondrial neurogastrointestinal encephalomyopathy carrying mutations on ANT1, C10ORF2 or POLG1, and TP genes.

RESULTS

Patients with at least one mutation in the exonuclease domain of POLG1 showed the highest frequency of individually rare point mutations only in the mtDNA control region; in addition, high levels, in terms of frequency and heteroplasmy, of recurrent mutations (A189G, T408A, and T414G) and alterations affecting the (HT)D310 region were detectable in many of the patients. Two homozygous POLG1 mutations, within the exonuclease domain, were able to induce an increased mutational burden also in fibroblasts from patients with PEO.

CONCLUSIONS

Specific POLG1 mutations directly affect the integrity of the mtDNA by reducing its proof-reading exonuclease activity, resulting in the accumulation of heteroplasmic levels of both randomly rare and recurrent point mutations in the skeletal muscle tissue and fibroblasts.

A mitochondrial tRNA(His) gene mutation causing pigmentary retinopathy and neurosensorial deafness

We have identified a heteroplasmic G to A mutation at position 12,183 of the mitochondrial transfer RNA Histidine (tRNA(His)) gene in three related patients. These phenotypes varied according to mutation heteroplasmy: one had severe pigmentary retinopathy, neurosensorial deafness, testicular dysfunction, muscle hypotrophy, and ataxia; the other two had only retinal and inner ear involvement. The mutation is in a highly conserved region of the T(psi)C stem of the tRNA(His) gene and may alter secondary structure formation. This is the first described pathogenic, maternally inherited mutation of the mitochondrial tRNA(His) gene.

Green tea extracts can counteract the modification of fatty acid composition induced by doxorubicin in cultured cardiomyocytes

Doxorubicin cardiotoxicity is associated with the generation of free radicals, and involves not only lipid peroxidation but also a decreased biosynthesis of highly unsaturated fatty acids, leading to significant modification in cardiomyocyte fatty acid composition. We have evaluated whether naturally occurring antioxidants could counteract this side-effect. Green tea is an excellent source of catechins; we supplemented cultured rat cardiomyocytes with different green tea extracts to relate their catechin content and composition to their ability in protecting cells against doxorubicin-induced damage. The determination of total lipid fatty acid composition, of conjugated diene production (indicator of lipid peroxidation), and of lactate dehydrogenase release revealed that supplementation with tea extracts could counteract significant modifications in the fatty acyl pattern due to doxorubicin exposure, although to different extents. These differences could be ascribed to the different total catechin content and to qualitative differences among the tea extracts, determined by HPLC analysis.

Ten-year survival results in metastatic renal cell cancer patients treated with monoimmunotherapy with subcutaneous low-dose interleukin-2

After more than ten years of clinical investigations, IL-2 immunotherapy appears to constitute the most effective treatment metastatic renal cell carcinoma (RCC),at least in terms of survival time. Moreover, it has been shown that comparable results may be achieved with different schedules of treatment, including intravenous high-dose or subcutaneous (SC) low-dose IL-2. Finally, it has been demonstrated that the association with interferon-alpha does not increase the efficacy of IL-2. Therefore, SC low-dose IL-2 alone may be considered as an adequate therapy for metastatic RCC. In fact, our previous studies with SC low-dose IL-2 alone have shown a 5-year survival time similar to that described with higher and more toxic doses of IL-2. This study was performed to analyze the 10-year survival results with SC low-dose IL-2 in metastatic RCC The study included 44 consecutive metastatic RCC patients, with a minimum follow-up of 120 months. One comlete immunotherapeutic cycle consisted of IL-2 at 3 million IU twice/day SC, 5 days/week for 6 consecutive weeks. In non-progressing patients, a second cycle was planned after a 21-day rest period. Complete response (CR) was achieved in only 2 out of 44 (4%) patients, while partial response (PR) was obtained in 8 out of /44 (18%) patients. Therefore, the response rate (CR + PR) was 10 out of 44 (22%), with a median response duration of 12 months. Stable disease (SD) occurred in 21 out of 44 (48%) patients,whereas the remaining 13 out of 44 (30%) patients had a progressive disease (PD). A 10-year survival was achieved in 2 out of 44 (5%) and the percent of survival at 10 years was significantly higher in patients with response or SD than in those with PD. This study confirms at 10 years the results previously referred to by other authors and by ourselves, in showing that the efficacy of IL-2 immunotherapy in terms of control of cancer growth is associated with a clear prolongation of the overall survival time in metastatic RCC.

A phase II study of chemoneuroimmunotherapy with platinum, subcutaneous low-dose interleukin-2 and the pineal neurohormone melatonin (P.I.M.) as a second-line therapy in metastatic melanoma patients progressing on dacarbazine plus interferon-alpha

Immunochemotherapeutic combinations containing IL-2 theoretically represent the most effective therapies for metastatic melanoma, particularly in association with cisplatin (CDDP); however, both IL-2 and CDDP have been generally utilized at high doses, with the consequence of considerable toxicity. According to psychoneuroimmunological knowledge, the antitumor activity of IL-2 has been proven to be enhanced by the immunomodulating pineal neurohormone melatonin (MLT), which has also been shown to increase the cytotoxicity of cancer chemotherapy and reduce its toxicity. On this basis, a study was planned with low-dose IL-2 and CDDP in association with MLT as a second-line therapy for metastatic melanoma patients progressing on dacarbazine plus interferon-alpha. The study included 13 evaluable patients. CDDP was injected i.v. at 30 mg/m2/day for 3 days every 21 days. IL-2 was administered s.c. at 3 million IU/day from days 4 to 9 and from days 11 to 16 of the cycle. Finally, MLT was given orally at 20 mg/day in the evening, every day without interruption. One patient obtained a complete response (CR), while partial response (PR) was achieved in 3 other patients. Therefore, the objective tumor response-rate (CR + PR) was 4 out of 13 (31%). A stable disease occurred in 5 patients, whereas the remaining 4 patients had a progressive disease. The treatment was extremely well-tolerated in all patients and, in particular, no CDDP-related neurotoxicity was observed. The results of this preliminary study would suggest that low-dose CDDP and IL-2 in association with the pineal hormone MLT (P.I.M. schedule), given as a second line therapy, is an effective and well-tolerated treatment for metastatic melanoma, with a clinical efficacy at least comparable to that obtained with a first-line therapy of dacarbazine plus interferon-alpha.

A novel missense adenine nucleotide translocator-1 gene mutation in a Greek adPEO family

Autosomal dominant progressive external ophthalmoplegia (adPEO) is caused by mutations in at least three different genes: ANT1 (chromosome 4q34-35), TWINKLE, and POLG. The ANT1 gene encodes the adenine nucleotide translocator-1 (ANT1). We identified a heterozygous T293C mutation of the ANT1 gene in a Greek family with adPEO. The resulting leucine to proline substitution likely modifies the secondary structure of the ANT1 protein. ANT1 gene mutations may account for adPEO in families with different ethnic backgrounds.

Retrospective study of a large population of patients affected with mitochondrial disorders: clinical, morphological and molecular genetic evaluation

Mitochondrial disorders are human genetic diseases with extremely variable clinical and genetic features. To better define them, we made a genotype-phenotype correlation in a series of 207 affected patients, and we examined most of them with six laboratory examinations (serum CK and basal lactate levels, EMG, cardiac and EEG studies, neuroradiology). We found that, depending on the genetic abnormality, hyperckemia occurs most often with either chronic progressive external ophthalmoplegia (CPEO) and ptosis or with limb weakness. Myopathic EMGs are more common than limb weakness, except in patients with A8344G mutations. Peripheral neuropathy, when present, is always axonal. About 80% of patients with A3243G and A8344G mutations have high basal lactate levels, whereas pure CPEO is never associated with increased lactate levels. Cardiac abnormalities mostly consist of conduction defects. Abnormalities on CT or MRI of the brain are relatively common in A3243G mutations independently of the clinical phenotype. Patients with multiple mtDNA deletions are somehow "protected" against the development of abnormalities with any of the tests. We conclude that, despite the phenotypic heterogeneity of mitochondrial disorders, correlation of clinical features and laboratory findings may give the clinician important clues to the genetic defect, allowing earlier diagnosis and counselling.

Beta-enolase deficiency, a new metabolic myopathy of distal glycolysis

A severe muscle enolase deficiency, with 5% of residual activity, was detected in a 47-year-old man affected with exercise intolerance and myalgias. No rise of serum lactate was observed with the ischemic forearm exercise. Ultrastructural analysis showed focal sarcoplasmic accumulation of glycogen beta particles. The enzyme enolase catalyzes the interconversion of 2-phosphoglycerate and phosphoenolpyruvate. In adult human muscle, over 90% of enolase activity is accounted for by the beta-enolase subunit, the protein product of the ENO3 gene. The beta-enolase protein was dramatically reduced in the muscle of our patient, by both immunohistochemistry and immunoblotting, while alpha-enolase was normally represented. The ENO3 gene of our patient carries two heterozygous missense mutations affecting highly conserved amino acid residues; a G467A transition changing a glycine residue at position 156 to aspartate, in close proximity to the catalytic site, and a G1121A transition changing a glycine to glutamate at position 374. These mutations were probably inherited as autosomal recessive traits since the mother was heterozygous for the G467A and a sister was heterozygous for the G1121A transition. Our data suggest that ENO3 mutations result in decreased stability of mutant beta-enolase. Muscle beta-enolase deficiency should be considered in the differential diagnosis of metabolic myopathies due to inherited defects of distal glycolysis.

Role of gamma-linolenic acid in counteracting doxorubicin-induced damage in cultured rat cardiomyocytes

The clinical usefulness of doxorubicin is limited by cardiotoxicity. We have demonstrated that doxorubicin has a dual negative effect on myocardial lipids, acting against highly unsaturated fatty acids (HUFAs) directly and desaturating/elongating enzymes required for their biosynthesis, thus decreasing linoleic and alpha -linolenic conversion to higher metabolites. Primary cultures of rat cardiomyocytes were challenged with different doxorubicin concentrations and doxorubicin exposure was followed by a 24-h recovery period in the absence or presence of serum, and of gamma -linolenic acid. Serum in the recovery medium did not appear to be essential for the restoration of the desaturating/elongating activities, and gamma -linolenic acid supplementation influenced only alpha -linolenic acid conversion. Serum, and particularly gamma-linolenic acid, were very important in increasing HUFA levels behind the pure biosynthesis. HUFA biosynthesis plays a role in counteracting doxorubicin toxicity, but it cannot completely overcome the depletion of these fatty acids; serum and exogenous gamma-linolenate are critical in filling the decreased HUFA pool.