SIRT3 & SIRT7: Potential Novel Biomarkers for Determining Outcome in Pancreatic Cancer Patients

PURPOSE

The sirtuin gene family has been linked with tumourigenesis, in both a tumour promoter and suppressor capacity. Information regarding the function of sirtuins in pancreatic cancer is sparse and equivocal. We undertook a novel study investigating SIRT1-7 protein expression in a cohort of pancreatic tumours. The aim of this study was to establish a protein expression profile for SIRT1-7 in pancreatic ductal adenocarcinomas (PDAC) and to determine if there were associations between SIRT1-7 expression, clinico-pathological parameters and patient outcome.

MATERIAL AND METHODS

Immunohistochemical analysis of SIRT1-7 protein levels was undertaken in a tissue micro-array comprising 77 resected PDACs. Statistical analyses determined if SIRT1-7 protein expression was associated with clinical parameters or outcome.

RESULTS

Two sirtuin family members demonstrated significant associations with clinico-pathological parameters and patient outcome. Low level SIRT3 expression in the tumour cytoplasm correlated with more aggressive tumours, and a shorter time to relapse and death, in the absence of chemotherapeutic intervention. Low levels of nuclear SIRT7 expression were also associated with an aggressive tumour phenotype and poorer outcome, as measured by disease-free and disease-specific survival time, 12 months post-diagnosis.

CONCLUSIONS

Our data suggests that SIRT3 and SIRT7 possess tumour suppressor properties in the context of pancreatic cancer. SIRT3 may also represent a novel predictive biomarker to determine which patients may or may not respond to chemotherapy. This study opens up an interesting avenue of investigation to potentially identify predictive biomarkers and novel therapeutic targets for pancreatic cancer, a disease that has seen no significant improvement in survival over the past 40 years.

SIRT2: tumour suppressor or tumour promoter in operable breast cancer?

PURPOSE

Sirtuins comprise a family of genes involved in cellular stress, survival and damage responses. They have been implicated in a range of diseases including cancer, with most information pertaining to their function in tumourigenesis being derived from in vitro studies, or model organisms. Their putative roles as tumour suppressors or tumour promoters remain to be validated in vivo. Little is known about their role in breast tumourigenesis. We sought to evaluate the seven sirtuin family members (SIRT1-7) in a human breast cancer cohort, in relation to clinico-pathological features and outcome of the disease.

MATERIALS AND METHODS

Immunohistochemical analysis of SIRT1-7 protein levels was undertaken in 392 oestrogen receptor (ER+ve) and 153 ER-ve breast tumour samples. SIRT1-7 transcriptional levels were assessed in normal (n=25), non-malignant (n=73) and malignant (n=70) breast tissue using Relative Quantitative Real Time PCR. Statistical analyses determined if SIRT1-7 transcription or protein expression was associated with clinical parameters or outcome.

RESULTS

In ER-ve tumours, high protein levels of nuclear SIRT2 were associated with reduced time to recurrence and disease-specific death. This association was only observed in Grade 3 tumours. In the ER+ve cohort, high SIRT2 nuclear levels were associated with shorter disease-free survival and time to recurrence whilst on Tamoxifen, in patients with Grade 3 tumours. Conversely, in Grade 2 tumours, high SIRT2 levels were associated with increased time to recurrence.

CONCLUSIONS

Our data suggest that SIRT2 is the sirtuin predominantly involved in breast tumourigenesis and prognosis. It indicates that SIRT2 acts as a tumour suppressor or tumour promoter dependent upon breast tumour grade.

Pathfinder cells provide a novel therapeutic intervention for acute kidney injury

Pathfinder cells (PCs) are a novel class of adult-derived cells that facilitate functional repair of host tissue. We used rat PCs to demonstrate that they enable the functional mitigation of ischemia reperfusion (I/R) injury in a mouse model of renal damage. Female C57BL/6 mice were subjected to 30 min of renal ischemia and treated with intravenous (i.v.) injection of saline (control) or male rat pancreas-derived PCs in blinded experimentation. Kidney function was assessed 14 days after treatment by measuring serum creatinine (SC) levels. Kidney tissue was assessed by immunohistochemistry (IHC) for markers of cellular damage, proliferation, and senescence (TUNEL, Ki67, p16(ink4a), p21). Fluorescence in situ hybridization (FISH) was performed to determine the presence of any rat (i.e., pathfinder) cells in the mouse tissue. PC-treated animals demonstrated superior renal function at day 14 post-I/R, in comparison to saline-treated controls, as measured by SC levels (0.13 mg/dL vs. 0.23 mg/dL, p<0.001). PC-treated kidney tissue expressed significantly lower levels of p16(ink4a) in comparison to the control group (p=0.009). FISH analysis demonstrated that the overwhelming majority of repaired kidney tissue was mouse in origin. Rat PCs were only detected at a frequency of 0.02%. These data confirm that PCs have the ability to mitigate functional damage to kidney tissue following I/R injury. Kidneys of PC-treated animals showed evidence of improved function and reduced expression of damage markers. The PCs appear to act in a paracrine fashion, stimulating the host tissue to recover functionally, rather than by differentiating into renal cells. This study demonstrates that pancreatic-derived PCs from the adult rat can enable functional repair of renal damage in mice. It validates the use of PCs to regenerate damaged tissues and also offers a novel therapeutic intervention for repair of solid organ damage in situ.

Interactions between MAP kinase and oestrogen receptor in human breast cancer

PURPOSE

The oestrogen receptor (ERα) may be activated in a ligand-dependent manner, via oestrogen, or in a ligand-independent manner, via signal transduction pathways. Mitogen Activated Protein Kinase (MAPK) is known to directly phosphorylate ERα at serine 118 in a ligand-independent manner. This study investigated the interaction between MAPK and ERα in breast cancer.

MATERIALS & METHODS

Immunohistochemical experiments were undertaken to determine the expression of MAPK, pMAPK and pER(ser118) in breast tumours to determine their clinical relevance. Immunofluorescent experiments were performed, on MCF-7 breast cancer cells, to monitor the phosphorylation and localisation of MAPK and ERα in response to oestrogen, heregulin and a MAPK inhibitor.

RESULTS

Oestrogen and Heregulin stimulated phosphorylation of ERα and its nuclear translocation, but heregulin induced this at levels much lower than those observed with oestrogen. Following stimulation with heregulin, but not oestrogen, treatment with MAPK inhibitor reduced the levels of nuclear pER(ser118). In cells treated with both oestrogen and heregulin, nuclear pER(ser118) was visible; but at levels comparable with heregulin treatment alone.

CONCLUSION

This study confirms that ligand-mediated phosphorylation is associated with rapid nuclear localisation of ERα, due to oestrogen binding. ERα is phosphorylated at serine 118 in a ligand-independent manner. Preventing nuclear translocation of pMAPK reduced the levels of ligand-independent, but not ligand-dependent phosphorylation of ERα. Co-stimulation with both oestrogen and heregulin suggested that heregulin mediated signalling determines the subcellular localisation of ERα. Activation of ERα by direct phosphorylation may result in its rapid deactivation due to degradation or nuclear export.

Is telomere length socially patterned? Evidence from the West of Scotland Twenty-07 Study

Lower socioeconomic status (SES) is strongly associated with an increased risk of morbidity and premature mortality, but it is not known if the same is true for telomere length, a marker often used to assess biological ageing. The West of Scotland Twenty-07 Study was used to investigate this and consists of three cohorts aged approximately 35 (N = 775), 55 (N = 866) and 75 years (N = 544) at the time of telomere length measurement. Four sets of measurements of SES were investigated: those collected contemporaneously with telomere length assessment, educational markers, SES in childhood and SES over the preceding twenty years. We found mixed evidence for an association between SES and telomere length. In 35-year-olds, many of the education and childhood SES measures were associated with telomere length, i.e. those in poorer circumstances had shorter telomeres, as was intergenerational social mobility, but not accumulated disadvantage. A crude estimate showed that, at the same chronological age, social renters, for example, were nine years (biologically) older than home owners. No consistent associations were apparent in those aged 55 or 75. There is evidence of an association between SES and telomere length, but only in younger adults and most strongly using education and childhood SES measures. These results may reflect that childhood is a sensitive period for telomere attrition. The cohort differences are possibly the result of survival bias suppressing the SES-telomere association; cohort effects with regard different experiences of SES; or telomere possibly being a less effective marker of biological ageing at older ages.

Socio-economic status is associated with epigenetic differences in the pSoBid cohort

BACKGROUND

Epigenetic programming and epigenetic mechanisms driven by environmental factors are thought to play an important role in human health and ageing. Global DNA methylation has been postulated as an epigenetic marker for epidemiological studies as it is reflective of changes in gene expression linked to disease. How epigenetic mechanisms are affected by psychological, sociological and biological determinants of health still remains unclear. The aim of this study was to investigate the relationship between socio-economic and lifestyle factors and epigenetic status, as measured by global DNA methylation content, in the pSoBid cohort, which is characterized by an extreme socio-economic and health gradient.

METHODS

DNA was extracted from peripheral blood leukocytes using the Maxwell® 16 System and Maxwell® 16 Blood DNA Purification kit (Promega, UK). Global DNA methylation was assessed using Methylamp™ Global DNA Methylation Quantification Ultra kit (Epigentek, USA). Associations between global DNA methylation and socio-economic and lifestyle factors were investigated in linear regression models.

RESULTS

Global DNA hypomethylation was observed in the most socio-economically deprived subjects. Job status demonstrated a similar relationship, with manual workers having 24% lower DNA methylation content than non-manual. Additionally, associations were found between global DNA methylation content and biomarkers of cardiovascular disease (CVD) and inflammation, including fibrinogen and interleukin-6 (IL-6), after adjustment for socio-economic factors.

CONCLUSIONS

This study has indicated an association between epigenetic status and socio-economic status (SES). This relationship has direct implications for population health and is reflected in further associations between global DNA methylation content and emerging biomarkers of CVD.

Telomere attrition and decreased fetuin-A levels indicate accelerated biological aging and are implicated in the pathogenesis of colorectal cancer

PURPOSE

Increasing chronological age is a risk factor for many types of cancer including colorectal. An understanding of the biology of aging and factors which regulate it may provide insight into cancer pathogenesis. The role of telomere biology in both the cancer and aging process could prove useful in this regard.

EXPERIMENTAL DESIGN

Using quantitative PCR, we determined telomere length in the peripheral blood leukocytes of 64 colorectal cancer (CRC) patients and 1,348 controls. We also measured telomere length in 32 colorectal tumor samples and matched normal tissue. We aimed to assess whether telomere lengths were reflected in circulating mediators of inflammation and redox control factors, including fetuin-A, a circulating modulator of calcium homeostasis.

RESULTS

CRC patients had shorter telomeres [adjusted mean ratio of relative telomere repeat copy number to single-copy gene number (RelT/S) = 0.61] compared with chronologically older controls (mean age = 75, adjusted mean RelT/S = 0.70; ANCOVA, P = 0.004). Telomere length in tumor tissue [median = 0.43, interquartile range (IQR) = 0.40] was significantly shorter than adjacent normal tissue (median = 0.65, IQR = 0.28; P = 0.004). Patients with low fetuin-A levels were shown to have significantly shorter telomeres (P = 0.041). Patients with rectal tumors had significantly higher levels of fetuin-A than those with colonic tumors (P = 0.045).

CONCLUSIONS

We have observed that patients with CRC display clear evidence of telomere attrition compared with controls. This is congruent with accelerated biological aging in the pathogenesis of CRC. An imbalance in redox control mechanisms and calcium homeostasis may be a contributing factor to telomere dynamics in our patients. Furthermore, fetuin-A levels can be used to distinguish between colon and rectal cancers.

Pancreatic-derived pathfinder cells enable regeneration of critically damaged adult pancreatic tissue and completely reverse streptozotocin-induced diabetes

We demonstrate that intravenous delivery of human, or rat, pancreas-derived pathfinder (PDP) cells can totally regenerate critically damaged adult tissue and restore normal function across a species barrier. We have used a mouse model of streptozotocin (STZ)-induced diabetes to demonstrate this. Normoglycemia was restored and maintained for up to 89 days following the induction of diabetes and subsequent intravenous delivery of PDP cells. Normal pancreatic histology also appeared to be restored, and treated diabetic animals gained body weight. Regenerated tissue was primarily of host origin, with few rat or human cells detectable by fluorescent in situ hybridization (FISH). Crucially, the insulin produced by these animals was overwhelmingly murine in origin and was both types I and II, indicative of a process of developmental recapitulation. These results demonstrate the feasibility of using intravenous administration of adult cells to regenerate damaged tissue. Critically, they enhance our understanding of the mechanisms relating to such repair and suggest a means for novel therapeutic intervention in loss of tissue and organ function with age.

High expression of sphingosine 1-phosphate receptors, S1P1 and S1P3, sphingosine kinase 1, and extracellular signal-regulated kinase-1/2 is associated with development of tamoxifen resistance in estrogen receptor-positive breast cancer patients

Various studies in cell lines have previously demonstrated that sphingosine kinase 1 (SK1) and extracellular signal-regulated kinase 1/2 (ERK-1/2) interact in an estrogen receptor (ER)-dependent manner to influence both breast cancer cell growth and migration. A cohort of 304 ER-positive breast cancer patients was used to investigate the prognostic significance of sphingosine 1-phosphate (S1P) receptors 1, 2, and 3 (ie, S1P1, S1P2, and S1P3), SK1, and ERK-1/2 expression levels. Expression levels of both SK1 and ERK-1/2 were already available for the cohort, and S1P1, S1P2, and S1P3 levels were established by immunohistochemical analysis. High membrane S1P1 expression was associated with shorter time to recurrence (P=0.008). High cytoplasmic S1P1 and S1P3 expression levels were also associated with shorter disease-specific survival times (P=0.036 and P=0.019, respectively). Those patients with tumors that expressed high levels of both cytoplasmic SK1 and ERK-1/2 had significantly shorter recurrence times than those that expressed low levels of cytoplasmic SK1 and cytoplasmic ERK-1/2 (P=0.00008), with a difference in recurrence time of 10.5 years. Similarly, high cytoplasmic S1P1 and cytoplasmic ERK-1/2 expression levels (P=0.004) and high cytoplasmic S1P3 expression and cytoplasmic ERK-1/2 expression levels (P=0.004) were associated with shorter recurrence times. These results support a model in which the interaction between SK1, S1P1, and/or S1P3 and ERK-1/2 might drive breast cancer progression, and these findings, therefore, warrant further investigation.

Is the biology of breast cancer changing? A study of hormone receptor status 1984-1986 and 1996-1997

Using archived tumours, those from 1984–1986 and 1996–1997 underwent immunohistochemistry for hormone receptors and grade analysis. A significant shift towards more ER-positive and low-grade disease was found; this appears to reflect screening practices, but could still influence survival.

Cellular senescence in pretransplant renal biopsies predicts postoperative organ function

Older and marginal donors have been used to meet the shortfall in available organs for renal transplantation. Post-transplant renal function and outcome from these donors are often poorer than chronologically younger donors. Some organs, however, function adequately for many years. We have hypothesized that such organs are biologically younger than poorer performing counterparts. We have tested this hypothesis in a cohort of preimplantation human renal allograft biopsies ( n = 75) that have been assayed by real-time polymerase chain reaction for the expression of known markers of cellular damage and biological aging, including CDKN2A, CDKN1A, SIRT2 and POT1. These have been investigated for any associations with traditional factors affecting transplant outcome (donor age, cold ischaemic time) and organ function posttransplant (serum creatinine levels). Linear regression analyses indicated a strong association for serum creatinine with pre-transplant CDKN2A levels ( p = 0.001) and donor age ( p = 0.004) at 6 months post-transplant. Both these markers correlated significantly with urinary protein to creatinine ratios ( p = 0.002 and p = 0.005 respectively), an informative marker for subsequent graft dysfunction. POT1 expression also showed a significant association with this parameter ( p = 0.05). Multiple linear regression analyses for CDKN2A and donor age accounted for 24.6% ( p = 0.001) of observed variability in serum creatinine levels at 6 months and 23.7% ( p = 0.001) at 1 year posttransplant. Thus, these data indicate that allograft biological age is an important novel prognostic determinant for renal transplant outcome.

Is the biology of breast cancer changing? A study of hormone receptor status and grade of breast cancers 1984-1986 and 1996-97

Abstract #3088

Introduction: There has been a significant improvement in breast cancer survival in the UK in recent decades. Changes in the molecular epidemiology of breast cancers may have contributed to this, but the existing evidence may be confounded by heterogeneity of laboratory protocols. This study aimed to re-analyse the molecular profile of breast cancers from two different time periods using archived tissue. Methods: Archived tumour samples from all breast cancer patients at two Glasgow hospitals between 1984-86 and 1996-97 were sought, and linked to clinicopathologic, screening, demographic and survival data. Patients in the 1984-6 cohort would not have been offered mammographic screening but those in 1996-97 would have. Samples were placed in tissue microarrays and underwent immunohistochemistry for ER, PR and Her-2 status with strict standardisation. H&E sections were constructed to assess tumour grade. Statistical analysis included Kaplan-Meier survival analysis and Cox's regression. Results: 900 tumour samples underwent staining. In 1984-86, 8% of tumours were grade 1 and 42.9% grade 3 but in 1996-97 14.9% were grade 1 and 36.8% grade 3 (p=0.009). This effect appeared to be exerted by the presence of screen detected tumours in 1996-97 (p for difference in grade distribution between symptomatic patients between 1984-86 and 1996-97 = 2). In 1984-86 64.2% of tumours were ER positive and in 1996-97 71.5% were ER positive (p=0.042). This did not appear to be a function of the screening programme as there was a significant rise in ER positivity in symptomatic patients between the two cohorts (p=0.024). 44.9% of tumours in 1984-86 and 49.9% of tumours in 1996-97 were PR positive (p=0.181). 21.5% of tumours in 1984-86 and 20.6% of tumours in 1996-97 were Her-2 positive (p=0.772). 5-year survival in 1984-1986 patients was significantly lower than in 1996-1997 patients (p&lt;0.001). When the effect of cohort on survival was adjusted for these changes in ER status and grade, cohort remained a significant independent factor. Conclusions: This study suggests a small but significant rise has occurred in the incidence of ER positive tumours in women in Glasgow. There has also been a shift in grade distribution of tumours, which is likely to be an effect of the NHS screening programme. The changes do not fully explain improvements in breast cancer survival but should be borne in mind when applying the results of clinical trials performed in the past to the women of today.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3088.

SIRT7 expression and epigenetic status determine variability in telomere length in breast cancer

Abstract #4052

Background: As cancer is a disease of ageing, factors involved in biological ageing may be informative in investigating the underlying mechanisms of cancer pathogenesis. How biological age is affected by epigenetic changes remains to be fully determined. This is pertinent to cancer pathogenesis, as epigenetic changes can increase the risk of neoplasia. We have investigated the biological age of breast tumours, using telomere length and the expression of sirtuin 7, a gene involved in the regulation of ribosome biosynthesis and previously demonstrated as potentially prognostic in breast cancer. We have evaluated these for association with epigenetic status.&#x2028; Materials and Methods: Telomere lengths and Sirtuin 7 (SIRT7) expression were determined using Q-PCR. Epigenetic status was determined using a Methylamp Global DNA methylation kit. Statistical analysis was performed using SPSS v15.&#x2028; Results: Chronological age was negatively associated with telomere length (p=0.013) and positively associated with methylation levels (p=0.007). Furthermore, telomere length showed a negative association with global methylation levels (p=0.002). Individuals with shorter telomeres were older and demonstrated higher levels of global DNA methylation. SIRT7 expression was positively associated with telomere length (p=0.01), but showed no association with methylation levels. Linear regression analysis indicated that SIRT7 expression accounted for 52.2% of the observed variability in telomere length (p=0.001) and methlyation for 33.4% (p&lt;0.001). Multiple linear regression analysis indicated that methylation status and SIRT7 expression combined accounted for 69.4% of the observed variability in telomere length. Chronological age was not a significant contributor in either analysis.&#x2028; Discussion: Cells with critically short telomeres present a high risk of becoming neoplastic, as they are biologically aged. This study has demonstrated that both SIRT7 expression and global methylation levels significantly influence telomere attrition in breast cancer. This is consistent with a scenario whereby the rate of biological ageing in breast tumours is influenced by telomere mediated epigenetic changes and mechanistically by cellular proliferation requirements. The latter is manifest through SIRT7 regulated ribosome biogenesis. These findings support the use of SIRT7 as a potential prognostic tool and therapeutic target in breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4052.

Expression levels of the JAK/STAT pathway in the transition from hormone-sensitive to hormone-refractory prostate cancer

The main cause of prostate cancer-related mortality is the development of hormone-refractory disease. Circulating serum levels of IL-6 are raised in hormone-refractory prostate cancer patients and evidence from cell line studies suggests that the IL-6R/JAK/STAT3 pathway may be involved in development of this disease. In the current study we investigate if expression levels of these family members are implicated in the development of hormone-refractory prostate cancer. Immunohistochemistry using IL-6R, JAK1, STAT3, pSTAT3(Tyr705) and pSTAT3(Ser727) antibodies was performed on 50 matched hormone-sensitive and hormone-refractory tumours pairs. An increase in expression of cytoplasmic IL-6 receptor, with the development of hormone-refractory prostate cancer was associated with reduced time to relapse (P=0.0074) while an increase in expression of cytoplasmic pSTAT3(Tyr705) was associated with reduced patient survival (P=0.0003). In addition, those patients with high expression of cytoplasmic pSTAT3(Tyr705) in their hormone-refractory tumours had significantly shorter time to death from biochemical relapse and overall survival in comparison to those patients with low expression of cytoplasmic pSTAT3(Tyr705) (P=0.002 and P=0.0027, respectively). Activation of STAT3, via phosphorylation is associated with reduced patient survival, suggesting that activation of the IL-6R/JAK/STAT3 pathway is involved with development of hormone-refractory prostate cancer.

Amplified in Breast Cancer 1 in Human Epidermal Growth Factor Receptor–Positive Tumors of Tamoxifen-Treated Breast Cancer Patients

PURPOSE

Amplified in breast cancer 1 (AIB1) is a member of the p160/steroid receptor coactivators family and is involved in estrogen-dependent gene transcription by reducing the antagonistic activity of tamoxifen-bound estrogen receptor-alpha (ER-alpha). The present study was carried out to test the hypothesis that AIB1 protein expression and/or gene amplification mediates tamoxifen resistance in breast cancer.

EXPERIMENTAL DESIGN

Immunohistochemistry using AIB1 antibody and fluorescence in situ hybridization using probes specific for AIB1 and chromosome 20 was done on 402 ER-alpha-positive tamoxifen-treated breast cancers.

RESULTS

AIB1 overexpression was not associated with relapse during treatment with tamoxifen. In contrast, high AIB1 expression in patients with human epidermal growth factor receptor (HER) 2- and HER3-overexpressing tumors or tumors expressing one or more of HER1, HER2, or HER3 (HER1-3 positive) was associated with an increased risk of relapse on tamoxifen [hazard ratio, 2.20; 95% confidence interval, 1.07-3.52 (P = 0.0416); hazard ratio, 2.42; 95% confidence interval, 1.32-4.43 (P = 0.0030), respectively]. AIB1 gene amplification was observed in 18 of 362 (5%) patients. High AIB1 gene copy number had no effect on overall or disease-free survival.

CONCLUSIONS

Data presented here support a role for AIB1 expression on relapse during tamoxifen treatment in hormone-responsive HER-expressing clinical breast cancers and support clinical evidence, suggesting a cross-talk between ER-alpha and growth factor receptor pathways through changes in expression of specific coactivator proteins, such as AIB1. This study highlights the potential that tumor profiling, using multiple markers of treatment response, may improve patient selection for endocrine treatment, such as tamoxifen or aromatase inhibitors.

Observer variation in immunohistochemical analysis of protein expression, time for a change?

AIM

Immunohistochemical analysis of protein expression is central to most clinical translational studies and defines patient treatment or selection criteria for novel drugs. Interobserver variation is rarely analysed despite recognition that this is a key area of potential inaccuracy. Therefore our aim was to examine observer variation and suggest the revision of current standards.

METHODS AND RESULTS

We analysed inter- and intra-observer variation, by interclass correlation coefficient (ICCC) and kappa statistics, in 8661 samples. Intra-observer assessment of nuclear, cytoplasmic and membrane staining for seven proteins in 1323 samples resulted in an ICCC of 0.94 and a kappa-value of 0.787. Interobserver reproducibility, assessed on 28 proteins by seven observer pairs in 8661 carcinomas, gave an ICCC of 0.90 and a kappa-value of 0.70. No significant effect of either antibody or cellular compartmentalization was observed.

CONCLUSION

We have demonstrated that ICCC is a consistent method to assess observer variation when a continuous scoring system is used, compared with kappa statistics, which depends on a categorical system. Given the importance of accurate assessment of protein expression in diagnostic and experimental medicine, we suggest raising thresholds for observer variation: ICCC of 0.7 should be regarded as the minimum acceptable standard, ICCC of 0.8 as good and ICCC of > or = 0.9 as excellent.

AKT activation predicts outcome in breast cancer patients treated with tamoxifen

Oestrogen receptor (ERalpha) expression is a strong predictor of response to endocrine therapy. The PI3K/AKT/mTOR signal transduction pathway has been implicated in endocrine resistance in vitro. The present study was carried out to test the hypothesis that AKT activation mediates tamoxifen resistance in clinical breast cancer. Immunohistochemistry (IHC) using AKT1-3, pan-AKT, pAKT (Thr-308), pAKT (Ser-473), pER (Ser-167), and pHER2 antibodies was performed on 402 ERalpha-positive breast carcinomas from patients treated with tamoxifen. High pAKT (Ser-473) activity (p = 0.0406) and low AKT2 expression (p = 0.0115) alone, or in combination [high pAKT (Ser-473)/low AKT2; 'high-risk' patient group] (p = 0.0014), predicted decreased overall survival in tamoxifen-treated patients with ERalpha-positive breast cancers. There was no significant association between tumour levels of AKT expression or activity and disease-free survival (DFS); however, the 'high-risk' patient group was significantly more likely to relapse (p = 0.0491). During tamoxifen treatment, neither AKT2 nor pAKT predicted DFS. Finally, activation of AKT, via phosphorylation, was linked to activation of both HER2 and ERalpha in this patient cohort. The data presented here show that the PI3K/AKT/mTOR pathway is associated with relapse and death in ERalpha-positive breast cancer patients treated with tamoxifen, supporting in vitro evidence that AKT mediates tamoxifen resistance. Patients with a 'high-risk' expression profile were at increased risk of death (hazard ratio 3.22, p = 0.002) relative to 'low-risk' patients, highlighting the potential that tumour profiling, with multiple IHC markers predictive of therapeutic response, may improve patient selection for endocrine therapies, eg tamoxifen or aromatase inhibitor-based treatments.

Impact of Pneumocystis carinii and cytomegalovirus on the course and outcome of atypical pneumonia in advanced human immunodeficiency virus disease

Patients undergoing bronchoscopy for possible pneumocystis pneumonia were studied retrospectively to characterize the impact of common viral pathogens on the course of advanced human immunodeficiency virus (HIV) disease and atypical pneumonia. In 327 episodes, Pneumocystis carinii was found in 220 (67%), cytomegalovirus (CMV) in 145 (44%), and herpes simplex virus in 16 (5%). Early deterioration in oxygenation and use of intensive care was less common in CMV-positive patients. Neither CMV nor P. carinii was a predictor of mortality in multivariate analyses. CMV was not associated with an increased prevalence of later CMV disease. Isolation of CMV from the bronchoalveolar lavage fluid of these patients was not an indication for antiviral therapy. Pulmonary shedding of CMV may be associated with a decreased inflammatory response to P. carinii. The outcome of HIV-associated atypical pneumonia where no clear pulmonary pathogen is found on routine evaluation was no better than that of treated P. carinii pneumonia.

The impact of concomitant viral pathogens on the course of Pneumocystis carinii pneumonia

A large retrospective study was conducted to evaluate the impact of culturing cytomegalovirus from the respiratory secretions of AIDS patients with Pneumocystis carinii pneumonia. Pneumocystis carinii was found in 220 (67%) of 327 episodes and cytomegalovirus was found in 106 (48%) of the P. carinii-positive patients. Cytomegalovirus-positive and -negative patients were similar at baseline and had a similar number of hospital days, but had a lower incidence of early deterioration in oxygenation, fewer intensive-care days, were less frequently intubated, and had a higher 30-day survival. The better short-term outcome of cytomegalovirus positive patients observed in this study may relate to the immunosuppressive effects of cytomegalovirus.