Immunoscore immune checkpoint using spatial quantitative analysis of CD8 and PD-L1 markers is predictive of the efficacy of anti- PD1/PD-L1 immunotherapy in non-small cell lung cancer

BACKGROUND

Anti-PD-1 and PD-L1 antibodies (mAbs) are approved immunotherapy agents to treat metastatic non-small cell lung cancer (NSCLC) patients. Only a minority of patients responds to these treatments and biomarkers predicting response are currently lacking.

METHODS

Immunoscore-Immune-Checkpoint (Immunoscore-IC), an in vitro diagnostic test, was used on 471 routine single FFPE-slides, and the duplex-immunohistochemistry CD8 and PD-L1 staining was quantified using digital-pathology. Analytical validation was performed on two independent cohorts of 206 NSCLC patients. Quantitative parameters related to cell location, number, proximity and clustering were analysed. The Immunoscore-IC was applied on a first cohort of metastatic NSCLC patients (n = 133), treated with anti-PD1 or anti-PD-L1 mAbs. Another independent cohort (n = 132) served as validation.

FINDINGS

Anti-PDL1 clone (HDX3) has similar characteristics as anti-PD-L1 clones (22C3, SP263). Densities of PD-L1+ cells, CD8+ cells and distances between CD8+ and PD-L1+ cells were quantified and the Immunoscore-IC classification was computed. Using univariate Cox model, 5 histological dichotomised variables (CD8 free of PD-L1+ cells, CD8 clusters, CD8 cells in proximity of PD-L1 cells, CD8 density and PD-L1 cells in proximity of CD8 cells) were significantly associated with Progression-Free Survival (PFS) (all P < 0.0001). Immunoscore-IC classification improved the discriminating power of prognostic model, which included clinical variables and pathologist PD-L1 assessment. In two categories, the Immunoscore-IC risk-score was significantly associated with patients' PFS (HR = 0.39, 95% CI (0.26-0.59), P < 0.0001) and Overall Survival (OS) (HR = 0.42, 95% CI (0.27-0.65), P < 0.0001) in the training-set. Further increased hazard ratios (HR) were found when stratifying patients into three-category Immunoscore-IC (IS-IC). All patients with Low-IS-IC progressed in less than 18 months, whereas PFS at 36 months were 34% and 33% of High-IS-IC patients in the training and validation sets, respectively.

INTERPRETATION

Immunoscore-IC is a powerful tool to predict the efficacy of immune-checkpoint inhibitors (ICIs) in patients with NSCLC.

FUNDING

Veracyte, INSERM, Labex Immuno-Oncology, Transcan ERAnet European project, ARC, SIRIC, CARPEM, Ligue Contre le Cancer, ANR, QNRF, INCa France, Louis Jeantet Prize Foundation.

An immune-related gene expression signature predicts benefit from adding atezolizumab to FOLFOXIRI plus bevacizumab in metastatic colorectal cancer

BACKGROUND

AtezoTRIBE phase II randomized study demonstrated that adding atezolizumab to first-line FOLFOXIRI (5fluoruracil, oxaliplatin, irinotecan) plus bevacizumab prolongs progression-free survival (PFS) of metastatic colorectal cancer (mCRC) patients, with a modest benefit among proficient mismatch repair (pMMR). DetermaIO is an immune-related 27-gene expression signature able to predict benefit from immune-checkpoint inhibition in triple-negative breast cancer. In this analysis of AtezoTRIBE, we investigated the predictive impact of DetermaIO in mCRC.

METHODS

mCRC patients unselected for MMR status were randomized(1:2) to FOLFOXIRI plus bevacizumab (control arm) or the same regimen with atezolizumab (atezolizumab arm). RT-qPCR by DetermaIO was performed on RNA purified from pre-treatment tumours of 132(61%) out of 218 enrolled patients. A binary result (IOpos versus IOneg) adopting the pre-established DetermaIO cut-point (0.09) was obtained, and an exploratory optimized cut-point (IOOPT) was computed in the overall population and in pMMR subgroup (IOOPTpos versus IOOPTneg).

RESULTS

DetermaIO was successfully determined in 122 (92%) cases, and 23 (27%) tumours were IOpos. IOpos tumours achieved higher PFS benefit from atezolizumab arm than IOneg (HR:0.39 versus 0.83, P interaction=0.066). In pMMR tumours (N=110), a similar trend was observed (HR:0.47 versus 0.93, P interaction=0.139). In the overall population, with the computed IOOPT cut-point (0.277), 16 (13%) tumours were IOOPTpos and they derived higher PFS benefit from atezolizumab than IOOPTneg(HR:0.10 versus 0.85, P interaction=0.004). Similar results were found in the pMMR subgroup.

CONCLUSIONS

DetermaIO may be useful to predict benefit of adding atezolizumab to first-line FOLFOXIRI plus bevacizumab in mCRC. The exploratory IOOPT cut-point should be validated in independent mCRC cohorts.

Dissecting tumor lymphocyte infiltration to predict benefit from immune-checkpoint inhibitors in metastatic colorectal cancer: lessons from the AtezoT RIBE study

BACKGROUND

Tumor immune cells influence the efficacy of immune-checkpoint inhibitors (ICIs) and many efforts aim at identifying features of tumor immune microenvironment able to predict benefit from ICIs in proficient mismatch repair (pMMR)/microsatellite stable (MSS) metastatic colorectal cancer (mCRC).

METHODS

We characterized tumor immune cell infiltrate, by assessing tumor-infiltrating lymphocytes (TILs), Immunoscore, Immunoscore-IC, and programmed death ligand-1 (PD-L1) expression in tumor samples of patients with mCRC enrolled in the AtezoTRIBE study, a phase II randomized trial comparing FOLFOXIRI/bevacizumab/atezolizumab to FOLFOXIRI/bevacizumab, with the aim of evaluating the prognostic and predictive value of these features.

RESULTS

Out of 218 patients enrolled, 181 (83%), 77 (35%), 157 (72%) and 162 (74%) specimens were successfully tested for TILs, Immunoscore, Immunoscore-IC and PD-L1 expression, respectively, and 69 (38%), 45 (58%), 50 (32%) and 21 (13%) tumors were classified as TILs-high, Immunoscore-high, Immunoscore-IC-high and PD-L1-high, respectively. A poor agreement was observed between TILs and Immunoscore or Immunoscore-IC (K of Cohen <0.20). In the pMMR population, longer progression-free survival (PFS) was reported for Immunoscore-high and Immunoscore-IC-high groups compared with Immunoscore-low (16.4 vs 12.2 months; HR: 0.55, 95% CI: 0.30 to 0.99; p=0.049) and Immunoscore-IC-low (14.8 vs 11.5 months; HR: 0.55, 95% CI: 0.35 to 0.85; p=0.007), respectively, with a significant interaction effect between treatment arms and Immunoscore-IC (p for interaction: 0.006) and a trend for Immunoscore (p for interaction: 0.13). No PFS difference was shown according to TILs and PD-L1 expression. Consistent results were reported in the overall population.

CONCLUSIONS

The digital evaluation of tumor immune cell infiltrate by means of Immunoscore-IC or Immunoscore identifies the subset of patients with pMMR mCRC achieving more benefit from the addition of the anti-PD-L1 to the upfront treatment. Immunoscore-IC stands as the most promising predictor of benefit from ICIs.

Prognostic and predictive value of Immunoscore and its correlation with ctDNA in stage II colorectal cancer

This study aimed to validate the prognostic value of Immunoscore (IS) in stage II colorectal cancer (CRC), and explore the roles of IS and circulating tumor DNA (ctDNA) in the adjuvant treatment for early-stage CRC. Resected tumor samples from stage II CRC patients were collected from the Sun Yat-sen University Cancer Center. The densities of CD3+ and CD8+ lymphocytes were quantified and converted to IS and classified into Low, Intermediate (Int), and High groups according to predefined cutoffs. A total of 113 patients were included in the study. Patients with IS-High, Int, and Low were 43 (38%), 62 (55%), and 8 (7%), respectively. Patients with IS-High had an excellent clinical outcome, with none recurring during a median follow-up of 3 years, including 15 (35%) clinical high-risk patients. The 3-year disease-free survival (DFS) was 100% for IS-High, 76% for IS-Int, and 47% for IS-Low (P < .001). In the multivariate Cox analysis, IS was the only significant parameter associated with DFS. IS-Int and IS-Low patients with adjuvant chemotherapy had improved DFS compared to those who did not receive adjuvant chemotherapy (HR = 0.3; 95% CI 0.1-0.92; P = .026). Among the 49 patients with postoperative ctDNA data, IS-High patients had the lowest ctDNA positivity rate, suggesting that they were most eligible for chemotherapy-free treatment. IS had a strong prognostic value in Chinese patients with stage II CRC and demonstrates its clinical utility. IS and ctDNA will jointly optimize the adjuvant treatment strategies for early-stage CRC.

The Immunoscore in Localized Urothelial Carcinoma Treated with Neoadjuvant Chemotherapy: Clinical Significance for Pathologic Responses and Overall Survival

Simple Summary

The prognosis of localized muscle-invasive bladder cancer is poor and the prognostic and predictive biomarkers of the response to treatment are lacking. We retrospectively investigated the role of the Immunoscore in the neoadjuvant setting, where the Immunoscore is a standardized quantitative assay of lymphocytes in the tumor microenvironment. We found it allowed for the stratification of patient prognoses and the prediction of response to neoadjuvant chemotherapy.

Abstract

(1) Background—The five-year overall survival (OS) of muscle-invasive bladder cancer (MIBC) with neoadjuvant chemotherapy and cystectomy is around 50%. There is no validated biomarker to guide the treatment decision. We investigated whether the Immunoscore (IS) could predict the pathologic response to neoadjuvant chemotherapy and survival outcomes. (2) Methods—This retrospective study evaluated the IS in 117 patients treated using neoadjuvant chemotherapy for localized MIBC from six centers (France and Greece). Pre-treatment tumor samples were immunostained for CD3+ and CD8+ T cells and quantified to determine the IS. The results were associated with the response to neoadjuvant chemotherapy, time to recurrence (TTR), and OS. (3) Results—Low (IS-0), intermediate (IS-1–2), and high (IS-3–4) ISs were observed in 36.5, 43.7, and 19.8% of the cohort, respectively. IS was positively associated with a pathologic complete response (pCR; p-value = 0.0096). A high IS was found in 35.7% of patients with a pCR, whereas it was found in 11.3% of patients without a pCR. A low IS was observed in 48.4% of patients with no pCR and in 21.4% of patients with a pCR. Low-, intermediate-, and high-IS patients had five-year recurrence-free rates of 37.2%, 36.5%, and 72.6%, respectively. In the multivariable analysis, a high IS was associated with a prolonged TTR (high vs. low: p = 0.0134) and OS (high vs. low: p = 0.011). (4) Conclusions—This study showed the significant prognostic and predictive roles of IS regarding localized MIBC.

Prognostic and predictive value of the Immunoscore in stage III colon cancer patients treated with oxaliplatin in the prospective IDEA France PRODIGE-GERCOR cohort study

BACKGROUND

The Immunoscore (IS), which prognostically classifies stage I-III colon cancer (CC) patients, was evaluated in the International Duration Evaluation of Adjuvant Therapy (IDEA) France cohort study investigating 3 versus 6 months of oxaliplatin-based adjuvant chemotherapy in stage III CC patients.

PATIENTS AND METHODS

Densities of CD3+ and CD8+ T cells in the tumor and invasive margin were determined by immunohistochemistry, quantified by digital pathology, and converted to IS. Mismatch repair status was determined by immunohistochemistry or by pentaplex PCR. Prediction of disease-free survival (DFS) by IS was analyzed by a multivariable Cox regression model in each study arm. Harrell's C-statistics were used to investigate the IS performance.

RESULTS

Samples of 1322 patients were available. IS Low, Intermediate (Int), and High were observed in 43.6%, 47.0%, and 9.4% of patients, respectively. IS Low identified patients at higher risk of relapse or death compared with Int + High [hazard ratio (HR) = 1.54; 95% confidence interval (CI) 1.24-1.93, P = 0.0001]. The 3-year DFS was 66.80% (95% CI 62.23-70.94) for IS Low and 77.14% (95% CI 73.50-80.35) for IS Int + High. In multivariable analysis, IS remained significantly independently associated with DFS (P = 0.003) when adjusted for sex, histological grade, T/N stage, and microsatellite instability. For mFOLFOX6-treated patients (91.6% of the cohort), a statistical significant interaction was observed for the predictive value of IS for treatment duration (3 versus 6 months) in terms of DFS (P = 0.057). IS Int + High significantly predicted benefit of 6 months of treatment (HR = 0.53; 95% CI 0.37-0.75; P = 0.0004), including clinically low- and high-risk stage III CC (all P < 0.001). Conversely, patients with IS Low (46.4%) did not significantly benefit from the 6-month mFOLFOX6 versus the 3-month mFOLFOX6.

CONCLUSIONS

The prognostic value of IS for DFS was confirmed in patients with stage III CC treated with oxaliplatin-based chemotherapy. Its predictive value for DFS benefit of longer duration of mFOLFOX6 adjuvant treatment was found in IS Int + High. These results will be validated in an external independent cohort. CLINICALTRIALS.

GOV REGISTRATION

NCT03422601; EudraCT Number: 2009-010384-16.

Semantic memory assessment in 15 patients with amyotrophic lateral sclerosis

INTRODUCTION

A total of 30 to 50% of amyotrophic lateral sclerosis patients suffer from cognitive disorders. The aim of the study is to characterize these disorders and to assess semantic memory in non-demented ALS patients. The secondary aim is to look for a link between disease type and neuropsychological characteristics.

METHOD

Patients were followed in an ALS center in Dijon. The following neuropsychological tests were used in this study: Folstein test, BREF test, verbal fluency, Isaac test, GRESEM test and TOP 30 test.

RESULTS

Fifteen ALS patients were included. Nine of them (60%) were suffering from a semantic memory disorder. There was no correlation between ALS characteristics and the semantic memory disorder.

DISCUSSION

This is the first study to reveal a semantic memory disorder in ALS. This result accentuates the hypothesis that ALS and semantic dementia are two phenotypes of the same degenerative process linked to TDP 43 proteinopathy.

Leptin and its potential interest in assisted reproduction cycles

BACKGROUND

Leptin, an adipose hormone, has been shown to control energy homeostasis and food intake, and exert many actions on female reproductive function. Consequently, this adipokine is a pivotal factor in studies conducted on animal models and humans to decipher the mechanisms behind the infertility often observed in obese women.

METHODS

A systematic PubMed search was conducted on all articles, published up to January 2015 and related to leptin and its actions on energy balance and reproduction, using the following key words: leptin, reproduction, infertility, IVF and controlled ovarian stimulation. The available literature was reviewed in order to provide an overview of the current knowledge on the physiological roles of leptin, its involvement in female reproductive function and its potential interest as a prognostic marker in IVF cycles.

RESULTS

Animal and human studies show that leptin communicates nutritional status to the central nervous system and emerging evidence has demonstrated that leptin is involved in the control of reproductive functions by acting both directly on the ovaries and indirectly on the central nervous system. With respect to the clinical use of leptin as a biomarker in IVF cycles, a systematic review of the literature suggested its potential interest as a predictor of IVF outcome, as high serum and/or follicular fluid leptin concentrations have correlated negatively with cycle outcome. However, these preliminary results remain to be confirmed.

CONCLUSION

Leptin regulates energy balance and female reproductive function, mainly through its action on hypothalamic-pituitary-ovarian function, whose molecular and cellular aspects are progressively being deciphered. Preliminary studies evaluating leptin as a biomarker in human IVF seem promising but need further confirmation.

Genomic Grade Index (GGI): feasibility in routine practice and impact on treatment decisions in early breast cancer

Purpose

Genomic Grade Index (GGI) is a 97-gene signature that improves histologic grade (HG) classification in invasive breast carcinoma. In this prospective study we sought to evaluate the feasibility of performing GGI in routine clinical practice and its impact on treatment recommendations.

Methods

Patients with pT1pT2 or operable pT3, N0-3 invasive breast carcinoma were recruited from 8 centers in Belgium. Fresh surgical samples were sent at room temperature in the MapQuant Dx™ PathKit for centralized genomic analysis. Genomic profiles were determined using Affymetrix U133 Plus 2.0 and GGI calculated using the MapQuant Dx® protocol, which defines tumors as low or high Genomic Grade (GG-1 and GG-3 respectively).

Results

180 pts were recruited and 155 were eligible. The MapQuant test was performed in 142 cases and GGI was obtained in 78% of cases (n=111). Reasons for failures were 15 samples with <30% of invasive tumor cells (11%), 15 with insufficient RNA quality (10%), and 1 failed hybridization (<1%). For tumors with an available representative sample (≥ 30% inv. tumor cells) (n=127), the success rate was 87.5%. GGI reclassified 69% of the 54 HG2 tumors as GG-1 (54%) or GG-3 (46%). Changes in treatment recommendations occurred mainly in the subset of HG2 tumors reclassified into GG-3, with increased use of chemotherapy in this subset.

Conclusion

The use of GGI is feasible in routine clinical practice and impacts treatment decisions in early-stage breast cancer.

Trial Registration

ClinicalTrials.gov NCT01916837, http://clinicaltrials.gov/ct2/show/NCT01916837

[Amyotrophic lateral sclerosis, a disease with a complex diagnosis]

Amyotrophic lateral sclerosis is a degenerative disease with no known cause, no specific presenting symptoms and which results in incapacity and disability. Diagnosis is often delayed. Multi-disciplinary care is essential.

Genomic grade adds prognostic value in invasive lobular carcinoma

BACKGROUND

The prognostic value of histologic grade (HG) in invasive lobular carcinoma (ILC) remains uncertain, and most ILC tumors are graded as HG2. Genomic grade (GG) is a 97-gene signature that improves the prognostic value of HG. This study evaluates whether GG may overcome the limitations of HG in ILC.

METHODS

Gene expression data were generated from frozen tumor samples, and GG calculated according to the expression of 97 genes. The prognostic value of GG was assessed in a stratified Cox regression model for invasive disease-free survival (IDFS) and overall survival (OS).

RESULTS

A total of 166 patients were classified by GG. HG classified 33 (20%) tumors as HG1, 120 (73%) as HG2 and 12 (7%) as HG3. GG classified 106 (64%) tumors as GG low (GG1), 29 (17%) as GG high (GG3) and 31 (19%) as equivocal (cases not classified as GG1 or GG3). The median follow-up time was 6.5 years. In multivariate analyses, GG was associated with IDFS [HR(GG3 vs GG1) 5.6 (2.1-15.3); P < 0.001] and OS [HR(GG3 vs GG1) 7.2, 95% CI (1.6-32.2); P = 0.01].

CONCLUSIONS

GG outperformed HG in ILC and added prognostic value to classic clinicopathologic variables, including nodal status.

Abstract P3-10-08: Combining Genomic Grade and NPI Refines Risk Group Classification

Background: The Nottingham Prognostic Index (NPI) is a clinically validated prognostic model which predicts survival for patients with early primary breast cancer. The NPI combines information on tumor size, lymph node stage and tumor grade and stratifies patients into risk groups useful for treatment decisions. Classically, NPI defines 5 risk categories: Excellent, Good, Moderate I, Moderate II and Poor Prognostic Group (EPG, GPG, MPGI, MPGII and PPG). However, the value of NPI to identify EPG patients has recently being challenged. The Genomic Grade Index (GGI) is a 97-gene test which has been shown to improve tumor grading by resolving the intermediate Histological Grade (HG) 2 tumors into high or low Genomic Grades. In this study, we investigated the potential of GGI to refine the NPI classification, and especially to discriminate patients with the lowest risk.

Material and methods:Breast cancer microarray profiles from node negative, untreated patients with the required clinical and pathological information were retrieved from 3 public databases. GGI was calculated using the Ipsogen MapQuant Dx® protocol which defines two classes, GG1 and GG3 (results falling in the CI are reported as Undetermined, “UD”). Standard NPI was calculated based on HG according to the usual formula: [0.2 x tumor size (cm) + HG(1-3) + LN stage (I-III)]. NPI scores were also calculated using GGI (“G-NPI”): the HG was replaced by the GG in the equation, and UD patients were given a value of 2 for tumor grade. Patients were classified into prognostic groups (cut-offs 2.4, 3.4 and 5.4) for both NPI (EPG, GPG, MPG and PPG) and G-NPI (G-EPG, G-GPG, G-MPG and G-PPG). NPI and G-NPI risk classifications were compared and prognostic performances were analyzed using Kaplan Meier survival curves (10-yr MFS).

Results:Unique microarray expression profiles with adequate MapQuant Dx® quality criteria and relevant clinical information were identified for 472 patients. HG was distributed as follows: 18 % HG1, 52 % HG2 and 30% HG3 with size ranging from 0.1 to 6 cm (mean = 2.1 cm). HG2 cases (n=246) were reclassified into 47% GG1 and 28% GG3, with 25% remaining UD. There were no patients classified in the PPG, using the standard NPI or the G-NPI. Comparison of risk group classification showed that G-NPI globally shifted patients from low to better prognostic groups: 28% of patients were classified in the G-EPG as opposed to only 12% in the EPG [Table 1]. Within the HG2 subgroup, none of the patients were classified in the EPG by standard NPI, while 75 patients were classified in this group by G-NPI. In the entire cohort, EPG and G-EPG 10-yrs MFS were comparable (82 and 88% resp.). In the HG2 subgroup, 10-yrs MFS was 92% for the G-EPG, 87 % for the G-GPG and 57% for the G-MPG.

Conclusion: Using GGI to calculate NPI scores provides additional information compared to standard NPI. This is particularly true in the HG2 group where G-NPI is able to identify patients matching the EPG definition with a 92% 10-yr MFS. Combining genomic information with NPI may facilitate adjuvant therapy decision making. This approach deserves further validation.

Prognostic Group Classification according to classic NPI and G-NPI

Trends in Incidence, Risk Factors, and Survival in Symptomatic Lacunar Stroke in Dijon, France, From 1989 to 2006

Background and Purpose— Lacunar infarcts are usually regarded as benign stroke, but population-based studies are required to assess the exact place of this stroke subtype in cerebrovascular pathology.

Methods— We evaluated trends in incidence rates, risk factor profiles, and survival rates in symptomatic lacunar stroke from a prospective population-based registry from 1989 to 2006.

Results— We recorded 2536 ischemic strokes. Among these, 715 (28%) were lacunar infarcts (354 men and 361 women). From 1989 to 2006, we observed a significant rise in the incidence of lacunar stroke in the 2 sexes considered together (relative risk, 1.02; 95% CI, 1.005 to 1.035; P =0.007), whereas the variation was not significant in either men or women when considered separately. Incidence rates significantly increased in young patients under 65 years old (relative risk, 1.049; 95% CI, 1.0175 to 1.0817; P =0.002). Concerning the distribution of cerebrovascular risk factors, lacunar stroke differed from nonlacunar stroke only with regard to the lower prevalence of a history of atrial fibrillation in the former ( P <0.001). For lacunar infarcts, survival rates were 96% at 1 month (95% CI, 0.94 to 0.97), 86% at 1 year (95% CI, 0.83 to 0.89), and 78% at 2 years (95% CI, 0.75 to 0.81) and were significantly higher than those for nonlacunar stroke (hazard ratio, 2.05; 95% CI, 1.70 to 2.47; P <0.001).

Conclusion— Our results suggest a significant increase in the incidence rates of lacunar stroke with a relatively good short-term prognosis in terms of survival. The association among hypertension, diabetes mellitus, and lacunar stroke was no stronger than the association between these 2 risk factors and nonlacunar stroke.

[Leptomeningeal dissemination after ethmoidal sinus adenocarcinoma surgery: a rare complication]

INTRODUCTION

Although rare, adenocarcinoma is the most frequent neoplasm of the ethmoid sinus and must be regarded as an occupational disease secondary to chronic wood dust exposure. Few cases with neurological metastasis have been reported.

CASE REPORT

We report the cases of two patients who developed a multiple cranial nerve disorder for the first case and a cauda equina syndrome for the second, after ethmoid adenocarcinoma surgery.

CONCLUSION

Diagnosis of carcinomatous meningitis is difficult and is based on clinical data, CSF analysis and gadolinium-enhanced T1-weighted brain and spinal cord MRI. The implication of surgery is discussed. Prognosis of such a disorder is poor.

A short region of the promoter of the breast cancer associated PLU-1 gene can regulate transcription in vitro and in vivo

The recently cloned gene PLU-1 shows restricted expression in adult tissues, with high expression being found in testis, and transiently in the pregnant mammary gland. However, both the gene and the protein product are specifically up-regulated in breast cancer. To investigate the control of expression of the PLU-1 gene, we have cloned and functionally characterised the 5' flanking region of the gene, which was found to contain another putative gene. Two transcription start sites of the PLU-1 gene were mapped by 5' RACE. A short proximal 249 bp region was defined using reporter gene assays, which encompasses the major transcription start site and exhibits a strong constitutive promoter activity in all cell lines tested. However, regions upstream of this sequence repress transcription more effectively in a non-malignant breast cell line as compared to breast cancer cell lines. The 249 bp region is GC-rich and includes consensus Sp1 sites, GC boxes, cAMP-responsive element (CRE) and other putative cis-elements. Mutational analysis showed that two intact conserved Sp1 binding sites (shown here to bind Sp1 and/or Sp3) are critical for constitutive promoter activity, while a negative role for a neighbouring GC box is indicated. The sequence of the core promoter is highly conserved in the mouse and Plu-1 expression in the mouse embryo has been documented. Using transgenesis, we therefore examined the ability of the 249 bp fragment to control expression of a reporter gene during embryogenesis. We found that not only is the core promoter sufficient to activate transcription in vivo, but that the expression of the reporter gene coincides both temporally and spatially with regions where endogenous Plu-1 is highly expressed. This suggests that tissue specific controlling elements are found within the short fragment and are functional in the embryonic environment.

Brca1 expression is regulated by a bidirectional promoter that is shared by the Nbr1 gene in mouse

The lack of functionally disrupting mutations of BRCA1 in sporadic breast tumours has suggested that other mechanisms, including dysregulation of gene expression, might be important in tumour development. We have analysed the control of expression of murine Brca1 and the adjacent gene, Nbr1, which lie head-to-head and are separated by less than 300 bp. Our results show that the expression of these two genes is under complex regulation, through a bidirectional promoter. Brca1 expression is driven by this single promoter, whereas Nbr1 expression is driven by this and one additional promoter, which generate two distinct transcripts, differing by the alternate use of the first exons. By comparison of mRNA transcription in adult murine tissues and also in the mammary gland during pregnancy and lactation, we show that Brca1 and Nbr1 expression is coordinately regulated in a spatial and temporal manner to produce quite different patterns of expression, even from the same promoter. The analysis of the murine and human syntenic region and its control has important implications for the regulation of human and murine BRCA1/NBR1 expression and the interpretation of animal models of disease.

BRCA1 methylation: a significant role in tumour development?

Cancer is a multistep process resulting from an accumulation of genetic mutations leading to dysfunction of critical genes, including tumour suppressor genes. Epigenetic changes are now also recognised as an important alternative mechanism of gene inactivation. In particular, aberrant methylation of the promoter region of a gene can lead to silencing ultimately contributing to the initiation or malignant progression of tumours. BRCA1, a breast and ovarian cancer susceptibility gene, is a tumour suppressor gene involved in the maintenance of genome integrity. Recent evidence for BRCA1 hypermethylation corroborates the view that this epigenetic alteration may play a determinant role in tumour suppressor silencing and possibly tumorigenesis. Here, we offer a summary of the data providing evidence for BRCA1 hypermethylation in tumours, and an investigation into the associated mechanism leading to BRCA1 silencing. We also discuss the impact of BRCA1 hypermethylation, as a form of epigenetic change, versus BRCA1 genetic mutations in tumour development.

Germline BRCA1 promoter deletions in UK and Australian familial breast cancer patients: Identification of a novel deletion consistent with BRCA1:psiBRCA1 recombination

Inherited susceptibility to breast cancer results from germline mutations in one of a number of genes including BRCA1. A significant number of BRCA1-linked familial breast cancer patients, however, have no detectable BRCA1 mutation. This could be due in part to the inability of commonly used mutation-detection techniques to identify mutations outside the BRCA1 coding region. This paper addresses the hypothesis that non-coding region mutations, specifically in the BRCA1 promoter, account for some of these cases. We describe a new and detailed restriction map of the 5' region of the BRCA1 gene including the nearby NBR2, psiBRCA1, and NBR1 genes and the isolation of a number of new informative hybridization probes suitable for Southern analysis. Using this information we screened DNA from lymphoblastoid cell-lines made from 114 UK familial breast cancer patients and detected one large deletion in the 5' region of BRCA1. We show that the breakpoints for this deletion are in BRCA1 intron 2 and between NBR2 and exon 2 of psiBRCA1, raising the possibility that this deletion arose via a novel mechanism involving BRCA1:psiBRCA1 recombination. We have also screened 60 familial breast cancer patients from the Australian population, using an amplification refractory mutation system (ARMS) technique described previously by our group, and found one patient with a genotype consistent with a BRCA1 promoter deletion. These findings indicate that germline BRCA1 promoter deletions are a rare and yet significant mutation event and that they could arise via a novel genetic mechanism.

Methylation of the BRCA1 promoter region in sporadic breast and ovarian cancer: correlation with disease characteristics

Reduced expression of BRCA1 has been reported in sporadic breast cancer, although the mechanisms underlying this phenomenon remain unclear. Abnormal methylation leading to silencing of tumour suppressor genes has been implicated in tumorigenesis in a wide range of sporadic cancers. Therefore, we sought to determine the frequency of methylation within the BRCA1 promoter region in a large group of sporadic invasive breast (n =96) and ovarian (n = 43) carcinomas using Southern analyses. Overall, methylation was detected in 11% of breast cancer cases and in 5% of ovarian tumours. Methylation of the BRCA1 promoter region was strongly correlated with lack of estrogen and progesterone receptor expression. It is clear from the frequency of abnormal methylation of the BRCA1 promoter region, that this cannot be the sole mechanism mediating the reduced expression of BRCA1 that has previously been reported to occur in the majority of invasive sporadic breast tumours. Nevertheless this study suggests that abnormal methylation of the BRCA1 promoter may be important in tumorigenesis in a subset of sporadic breast and ovarian cancers.

Identification of a C/G polymorphism in the promoter region of the BRCA1 gene and its use as a marker for rapid detection of promoter deletions

Reduced expression of BRCA1 has been implicated in sporadic breast cancer, although the mechanisms underlying this phenomenon remain unclear. To determine whether regulatory mutations could account for the reduced expression, we screened the promoter region by sequencing in 20 patients with sporadic disease. No mutations were detected; however, a new polymorphism consisting of a C-to-G base change within the beta-promoter was identified, with the frequency of the G allele being 0.34. Close to complete linkage disequilibrium was found between this marker and the Pro871 Leu polymorphism, situated in exon 11, which has previously been shown not to be associated with breast or ovarian cancer. This indicates that the C/G polymorphism is also unlikely to play a role in either disease. However, the strength of linkage disequilibrium between these markers permitted their use for rapid screening for genomic deletions within BRCA1. A series of 214 cases with familial breast cancer were analysed using this approach; 88/214 were heterozygous for the promoter polymorphism, thereby excluding a deletion in this region. Among the remaining patients, one hemizygous case reflecting a promoter deletion was successfully identified. Therefore, this study indicates that deletions within the beta-promoter region of BRCA1 are an uncommon event in familial breast cancer. Furthermore, it suggests that mutations within the BRCA1 promoter are unlikely to account for the reported decreased expression of BRCA1 in sporadic disease.

Genetic polymorphism of induction of CYP1A1 (EROD) activity

CYP1A1 is a cytochrome P450 which is inducible by polycyclic aromatic hydrocarbons (PAH). This induction is mediated via the Ahr locus which encodes the cytosolic Aryl hydrocarbon receptor. The induced activity of CYP1A1 can be measured in vitro by the ethoxyresorufin-O-deethylase (EROD) activity in lymphocytes after induction by benz(a)anthracene (B(a)A). Our purpose was to determine, using this assay, the genetic polymorphism of CYP1A1 induction. With this aim, a population and family study was undertaken. Using the statistical SKUMIX method, a bimodal distribution (two peaks) of the induced EROD activity among 102 unrelated individuals was obtained. We were unable to discriminate three classes of CYP1A1 induction phenotype since a trimodal distribution did not significantly improve the fit to the data (chi 2(1) = 0.37, p > 0.9). Segregation analysis performed on 57 nuclear families gave evidence of a major gene effect together with a polygenic component. The frequency of the high induction allele is equal to 0.11 with dominance on the low induction allele. This is an accordance with two distributions, with individuals showing low and high CYP1A1 induction phenotypes in proportions of 89% and 21% respectively. However, some degree of overlap between the two distributions prevented a clear genotype classification on the basis of the phenotype measured with the EROD assay. Further analyses should not be made with a dichotomized phenotype (low and high inducers) but should use quantitative measurements.

A population and family study of CYP1A2 using caffeine urinary metabolites

CYP1A2 is a cytochrome P450 which is inducible by polycyclic aromatic hydrocarbons. This induction could be mediated via the Ah locus, which encodes a cytosolic receptor responsible for the regulation of the CYP1A1 gene. Enzyme activity in vivo can be measured by the urinary caffeine metabolite ratio (AFMU + 1X + 1U)/17U. Our goal was to determine, using this ratio, the possible existence of a genetic polymorphism in CYP1A2 induction. For this purpose, a population and family study, including smokers, were undertaken. In a first step, we investigated factors influencing enzyme activity in a population of 245 unrelated individuals. The induction effect of smoking and inhibiting effect of oral contraceptive use were confirmed. None of the other factors examined (age, sex, level of cigarette consumption, nicotine or tar amounts, filter, inhalation) accounted for the interindividual variability in the metabolic ratio. Using the statistical SKUMIX method, a unimodal (one peak) distribution of the ratio was concluded in 164 unrelated smokers, since a second distribution did not significantly improve the fit to the data (chi 2(1) = 1.39, P > 0.2). Segregation analysis was performed on 68 nuclear families and no major gene effect could be shown. Furthermore, the polygenic model did not provide a higher likelihood than the sporadic one, which argues against the existence of any familial resemblance. Although we cannot rule out the possibility that some environmental factors could obscure the phenotypes and occult a genetic determinism, we conclude that genetic factors are probably negligible in the determination of CYP1A2 activity measured by this method.(ABSTRACT TRUNCATED AT 250 WORDS)

[Computed tomography aspects of cerebral toxoplasmosis in AIDS]

We followed by CT 19 AIDS patients with cerebral toxoplasmosis. Diagnosis of cerebral toxoplasmosis was assessed on radiological and clinical basis, including the therapeutic response. CT allowed to confirm brain lesions (40 lesions in 19 patients) and to follow the evolution with treatment. Analysis of the CT features of these brain lesions permits to define some characteristic findings, though not pathognomonic. These lesions share common characteristics with other granulomatous diseases or with brain abscesses. The most frequently observed features are: target lesions (74%) with contrast enhancement (95%), frequently multiple (53%), associated with a hypodense area of oedema (100%), and responsible for a mass effect (79%). Under treatment, we observed improvement in 89%, resulting either in complete disappearance of the lesions (16%), disappearance of one or more contrast enhancing (46%) or hypodense (6%) areas, or volumetric regression of the hypodensities (50%). We conclude that CT is a good first-step examination for the detection and follow-up of cerebral toxoplasmosis in AIDS patients. MRI, a method with a higher sensitivity but still less accessible, may be considered at the present time as a second-step examination for those patients with solitary lesions on CT, or for symptomatic patients with normal CT.

[Obstruction of the sigmoid colon due to an ovarian metastasis of colonic origin]

The authors present a case of left ovarian metastasis from colon carcinoma causing sigmoid obstruction. On US and CT the ovarian mass appears as a primary malignant lesion. The lesion caused a regular sigmoid stenosis which mimicked, on barium enema, a volvulus and screened the primary lesion.