Assessment of aberrant DNA methylation two years after paediatric critical illness: a pre-planned secondary analysis of the international PEPaNIC trial

Critically ill children requiring intensive care suffer from impaired physical/neurocognitive development 2 y later, partially preventable by omitting early use of parenteral nutrition (early-PN) in the paediatric intensive-care-unit (PICU). Altered methylation of DNA from peripheral blood during PICU-stay provided a molecular basis hereof. Whether DNA-methylation of former PICU patients, assessed 2 y after critical illness, is different from that of healthy children remained unknown. In a pre-planned secondary analysis of the PEPaNIC-RCT (clinicaltrials.gov-NCT01536275) 2-year follow-up, we assessed buccal-mucosal DNA-methylation (Infinium-HumanMethylation-EPIC-BeadChip) of former PICU-patients (N = 406 early-PN; N = 414 late-PN) and matched healthy children (N = 392). CpG-sites differentially methylated between groups were identified with multivariable linear regression and differentially methylated DNA-regions via clustering of differentially methylated CpG-sites using kernel-estimates. Analyses were adjusted for technical variation and baseline risk factors, and corrected for multiple testing (false-discovery-rate <0.05). Differentially methylated genes were functionally annotated (KEGG-pathway database), and allocated to three classes depending on involvement in physical/neurocognitive development, critical illness and intensive medical care, or pre-PICU-admission disorders. As compared with matched healthy children, former PICU-patients showed significantly different DNA-methylation at 4047 CpG-sites (2186 genes) and 494 DNA-regions (468 genes), with most CpG-sites being hypomethylated (90.3%) and with an average absolute 2% effect-size, irrespective of timing of PN initiation. Of the differentially methylated KEGG-pathways, 41.2% were related to physical/neurocognitive development, 32.8% to critical illness and intensive medical care and 26.0% to pre-PICU-admission disorders. Two years after critical illness in children, buccal-mucosal DNA showed abnormal methylation of CpG-sites and DNA-regions located in pathways known to be important for physical/neurocognitive development.

Physical, Emotional/Behavioral, and Neurocognitive Developmental Outcomes From 2 to 4 Years After PICU Admission: A Secondary Analysis of the Early Versus Late Parenteral Nutrition Randomized Controlled Trial Cohort

OBJECTIVES

PICU patients face long-term developmental impairments, partially attributable to early parenteral nutrition (PN) versus late-PN. We investigated how this legacy and harm by early-PN evolve over time.

DESIGN

Preplanned secondary analysis of the multicenter PEPaNIC-RCT (ClinicalTrials.gov, NCT01536275) that enrolled 1,440 critically ill children from 2012 to 2015 and its 2- (2014-2018) and 4-year (2016-2019) cross-sectional follow-up studies.

SETTING

PICUs of Leuven (Belgium), Rotterdam (The Netherlands), and Edmonton (Canada).

PATIENTS

Patients and demographically matched healthy control children that underwent longitudinal assessment for physical/emotional/behavioral/neurocognitive functions at both follow-up time points.

INTERVENTIONS

In the PEPaNIC-RCT, patients were randomly allocated to early-PN versus late-PN.

MEASUREMENTS AND MAIN RESULTS

This within-individual longitudinal study investigated changes in physical/emotional/behavioral/neurocognitive functions from 2 to 4 years after PICU admission for 614 patients (297 early-PN and 317 late-PN, tested at mean ± sd age 5.4 ± 4.2 and 7.3 ± 4.3 yr) and for 357 demographically matched healthy children tested at age 5.6 ± 4.3 and 7.5 ± 4.3 years. We determined within-group time-courses, interaction between time and group, and independent impact of critical illness and early-PN on these time-courses. Most deficits in patients versus healthy children remained prominent over the 2 years ( p ≤ 0.01). Deficits further aggravated for height, body mass index, the executive function metacognition, intelligence, motor coordination (alternating/synchronous tapping), and memory learning-index, whereas verbal memory deficits became smaller (working/immediate/delayed memory) ( p ≤ 0.05). Adjustment for risk factors confirmed most findings and revealed that patients "grew-into-deficit" for additional executive functions (flexibility/emotional control/total executive functioning) and "grew-out-of-deficit" for additional memory functions (recognition/pictures) ( p ≤ 0.05). Time-courses were largely unaffected by early-PN versus late-PN, except for weight loss and limited catch-up for visual-motor integration and alertness in early-PN patients ( p ≤ 0.05).

CONCLUSIONS

From 2- to 4-year post-PICU admission, developmental impairments remained prominent. Within that time-window, impaired growth in height, executive functioning and intelligence aggravated, and impaired memory and harm by early-PN only partially recovered. Impact on development into adulthood requires further investigation.

Impact of critical illness and withholding of early parenteral nutrition in the pediatric intensive care unit on long-term physical performance of children: a 4-year follow-up of the PEPaNIC randomized controlled trial

Background

Many critically ill children face long-term developmental impairments. The PEPaNIC trial attributed part of the problems at the level of neurocognitive and emotional/behavioral development to early use of parenteral nutrition (early-PN) in the PICU, as compared with withholding it for 1 week (late-PN). Insight in long-term daily life physical functional capacity after critical illness is limited. Also, whether timing of initiating PN affects long-term physical function of these children remained unknown.

Methods

This preplanned follow-up study of the multicenter PEPaNIC randomized controlled trial subjected 521 former critically ill children (253 early-PN, 268 late-PN) to quantitative physical function tests 4 years after PICU admission in Leuven or Rotterdam, in comparison with 346 age- and sex-matched healthy children. Tests included handgrip strength measurement, timed up-and-go test, 6-min walk test, and evaluation of everyday overall physical activity with an accelerometer. We compared these functional measures for the former critically ill and healthy children and for former critically ill children randomized to late-PN versus early-PN, with multivariable linear or logistic regression analyses adjusting for risk factors.

Results

As compared with healthy children, former critically ill children showed less handgrip strength (p < 0.0001), completed the timed up-and-go test more slowly (p < 0.0001), walked a shorter distance in 6 min (p < 0.0001) during which they experienced a larger drop in peripheral oxygen saturation (p ≤ 0.026), showed a lower energy expenditure (p ≤ 0.024), performed more light and less moderate physical activity (p ≤ 0.047), and walked fewer steps per day (p = 0.0074). Late-PN as compared with early-PN did not significantly affect these outcomes.

Conclusions

Four years after PICU admission, former critically ill children showed worse physical performance as compared with healthy children, without impact of timing of supplemental PN in the PICU. This study provides further support for de-implementing the early use of PN in the PICU.

Trial registration ClinicalTrials.gov, NCT01536275; registered on February 22, 2012.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04010-3.

Differential DNA methylation by early versus late parenteral nutrition in the PICU: a biological basis for its impact on emotional and behavioral problems documented 4 years later

Background

The PEPaNIC multicenter randomized controlled trial (RCT) has shown that early administration of supplemental parenteral nutrition (early-PN) as compared with withholding PN for 1 week (late-PN) induced long-term internalizing, externalizing and total emotional/behavioral problems in critically ill children, as observed 4 years later. Early-PN was further shown to alter the methylation status of 37 CpG-sites in leukocyte DNA between admission and discharge from the pediatric intensive care unit (PICU). In a preplanned subanalysis of the PEPaNIC trial, we now investigated whether the altered methylation of these CpG-sites could statistically explain the negative impact of early-PN on emotion/behavior documented 4 years after PICU admission.

Results

The combination of DNA methylation data and data on behavior 4 years after PICU admission was available for 403 of the 1440 patients (aged 0–17 years at PICU admission) who were included in the PEPaNIC RCT (192 early-PN and 211 late-PN patients). Mediation analyses with use of bootstrapped multivariable non-linear regression analyses adjusted for baseline risk factors revealed that the adverse alterations by early-PN in methylation of the 37 CpG-sites together statistically explained its harmful impact on internalizing, externalizing and total emotional/behavioral problems. When adding the methylation status of the 37 CpG-sites to the models, the explanatory power improved with a 1.710 to 1.851-fold increase, and the impact of the altered methylation status of the CpG-sites explained the impact of the randomization to early-PN versus late-PN.

Conclusions

Abnormal DNA methylation induced by the early use of PN in the PICU provides a biological basis for its long-term harmful effect on emotion/behavior of critically ill children 4 years after PICU admission.

Trial Registration ClinicalTrials.gov NCT01536275, registered February 17, 2012, https://clinicaltrials.gov/ct2/show/NCT01536275.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01124-3.

Solitary fibrous tumor of the adrenal gland – its biological behavior and report of a new case

Introduction

A solitary fibrous tumor (SFT) is an uncommon neoplasm of mesenchymal and probably fibroblastic origin, occurring mainly in the extremities, and pleura. However, a primary involvement of endocrine organs is rare and even exceptional when found in the adrenal gland. Hereby, we describe the 10th report of an adrenal SFT.

Case presentation

A 77-year old man was diagnosed with a lesion in the right adrenal gland during a urologic indicated computed tomography (CT). No symptoms and laboratory anomalies were reported indicating any endocrine activity. Follow up CT-scans showed progressive growth of the nodule for which the patient underwent laparoscopic right adrenalectomy. Histological examination showed a hypercellular spindle cell neoplasm with elongated nuclei and a low mitotic index. The vessels were arranged in a hemangiopericytoma-like pattern with a slight sclerosing appearance. Immunohistochemistry showed a positive staining of neoplastic cells for STAT6, CD-34 and Bcl-2. Translocation analysis using RT-PCR showed no NAB2-STAT6 fusion. The specimen was confirmed as a hypercellular variant of an adrenal SFT.

Discussion

SFT is a rare neoplasm when occurring in the adrenal gland. Differential diagnosis can be broad because of no defined pathognomonic morphological characteristics. However, NAB2-STAT6 gene fusions are considered a molecular hallmark of SFTs. Therefore, STAT6 immunohistochemistry is a valuable diagnostic tool in differentiating between SFT and histologic mimics. After diagnosing SFT, its biological behavior is difficult to predict. SFTs are mostly benign tumors. Nonetheless, a histological benign-appearing SFT can show malignant clinical characteristics impeding assessment of proper follow up. However, malignancy has not been previously reported in any adrenal SFT case report.

Time course of altered DNA methylation evoked by critical illness and by early administration of parenteral nutrition in the paediatric ICU

BACKGROUND

A genome-wide study identified de novo DNA methylation alterations in leukocytes of children at paediatric intensive care unit (PICU) discharge, offering a biological basis for their impaired long-term development. Early parenteral nutrition (early-PN) in PICU, compared with omitting PN in the first week (late-PN), explained differential methylation of 23% of the affected CpG-sites. We documented the time course of altered DNA methylation in PICU and the impact hereon of early nutritional management.

RESULTS

We selected 36 early-PN and 36 late-PN matched patients, and 42 matched healthy children. We quantified DNA methylation on days 3, 5 and 7 for the 147 CpG-sites of which methylation was normal upon PICU admission in this subset and altered by critical illness at PICU discharge. Methylation in patients differed from healthy children for 64.6% of the 147 CpG-sites on day 3, for 72.8% on day 5 and for 90.5% on day 7 as revealed by ANOVA at each time point. Within-patients methylation time course analyses for each CpG-site identified different patterns based on paired t test p value and direction of change. Rapid demethylation from admission to day 3 occurred for 76.2% of the CpG-sites, of which 67.9% remained equally demethylated or partially remethylated and 32.1% further demethylated beyond day 3. From admission to day 3, 19.7% of the CpG-sites became hypermethylated, of which, beyond day 3, 34.5% remained equally hypermethylated or partially demethylated again and 65.5% further hypermethylated. For 4.1% of the CpG-sites, changes only appeared beyond day 3. Finally, for the CpG-sites affected by early-PN on the last PICU day, earlier changes in DNA methylation were compared for early-PN and late-PN patients, revealing that 38.9% were already differentially methylated by day 3, another 25.0% by day 5 and another 13.9% by day 7.

CONCLUSIONS

Critical illness- and early-PN-induced changes in DNA methylation occurred mainly within 3 days. Most abnormalities were at least partially maintained or got worse with longer time in PICU. Interventions targeting aberrant DNA methylation changes should be initiated early.

Surgical management of acquired rectourethral fistula: a retrospective analysis of 52 consecutive patients

BACKGROUND

Acquired rectourethral fistula (RUF) is an uncommon complication mostly resulting from surgery or radiation. Standardization of the surgical management is lacking. The aim of this study was to report our experience with surgery for RUF.

METHODS

This was a retrospective study of a prospectively maintained clinical database. The surgical strategy was tailored to complexity of RUF, presence of sepsis, history of radiation and residual urinary/fecal functionality. Outcomes measured were RUF closure and permanent fecal/urinary diversion. Impact of radiotherapy was also assessed.

RESULTS

Between November 2002 and January 2019, 52 patients were identified (100% males). Median follow-up was 10.5 (0.5-16.8) years. Three patients had RUF closure after conservative management. The remaining 49 patients had a total of 76 procedures. The cumulative closure rate after the first, second and third attempt was 55.1%, 85.7% and 95.9%, respectively. Fistula closure together with preservation of the fecal and urinary function was achieved in 49%, 65.3% and 67.3% after the first, second and third repair, respectively. The overall success rate for transanal, transperineal, restorative transabdominal and non-restorative transabdominal procedures was 35.7%, 64.3%, 57.1% and 94.1%, respectively. A significantly higher rate of urinary/intestinal stomas was observed in the irradiated vs non-irradiated patients (84.2% vs 42.4%; p = 0.004).

CONCLUSIONS

Surgery ensured healing in 96% of the patients. Radiotherapy led to higher rate of permanent urinary/fecal diversion. Nearly all irradiated patients who had transabdominal repair end up with a definitive stoma. When transperineal repair with gracilis flap interposition was used, the rate of fistula closure approached 90%. A treatment algorithm is proposed.

Long-term developmental effect of withholding parenteral nutrition in paediatric intensive care units: a 4-year follow-up of the PEPaNIC randomised controlled trial

BACKGROUND

The PEPaNIC randomised controlled trial, which recruited 1440 critically ill infants and children in 2012-15, showed that withholding parenteral nutrition for 1 week (late-parenteral nutrition), compared with early supplementation within 24 h of admission to the paediatric intensive care unit (early-parenteral nutrition), prevented infections, accelerated recovery, and improved neurocognitive development assessed 2 years later. Because several neurocognitive domains can only be thoroughly assessed from age 4 years onwards, we aimed to determine the effect of late-parenteral nutrition versus early-parenteral nutrition on physical, neurocognitive, and emotional and behavioural development 4 years after randomisation.

METHODS

This is a preplanned, blinded, 4-year follow-up study of participants included in the PEPaNIC trial (done at University Hospitals Leuven, Belgium; Erasmus Medical Centre Sophia Children's Hospital, Rotterdam, Netherlands; and Stollery Children's Hospital, Edmonton, AB, Canada) and of matched healthy children. Studied outcomes were anthropometrics; health status; parent-reported or caregiver-reported executive functions, and emotional and behavioural problems; and clinical tests for intelligence, visual-motor integration, alertness, motor coordination, and memory. Through multivariable linear and logistic regression analyses, after imputation for missing values (≤30%) and adjustment for risk factors, we investigated the effect of early-parenteral nutrition versus late-parenteral nutrition. This trial is registered with ClinicalTrials.gov, NCT01536275.

FINDINGS

Between March 8, 2016, and Nov 8, 2019, 684 children from the original PEPaNIC trial (356 from the late-parenteral nutrition group and 328 from the early-parenteral nutrition group) were assessed for neurocognitive development at 4-years follow-up. Compared with the control group (369 healthy children), children who had critical illness had lower height (β-estimate -2·11 [95% CI -3·15 to -1·06]; p<0·0001) and head circumference (-0·42 [-0·67 to -0·18]; p=0.00077); and worse health status (eg, hospital admission odds ratio 4·27 [95% CI 3·12 to 5·84]; p<0·0001), neurocognitive (eg, parent-reported or caregiver-reported total executive functioning β-estimate 3·57 [95% CI 1·95 to 5·18], p<0·0001; total intelligence quotient -7·35 [-9·31 to -5·39], p<0·0001), and parent-reported or caregiver-reported emotional and behavioural developmental outcomes (internalising 2·73 [1·19 to 4·28], p=0·00055; externalising 1·63 [0·19 to 3·08], p=0·027; and total behavioural problems 2·95 [1·44 to 4·46], p=0·00013), adjusted for risk factors. Outcomes were never worse in the late-parenteral nutrition group compared with the early-parenteral nutrition group, but patients in the late-parenteral nutrition group had fewer parent-reported or caregiver-reported internalising (β-estimate -1·88 [95% CI -3·69 to -0·07]; p=0·042), externalising (-1·73 [-3·43 to -0·03]; p=0·046), and total emotional and behavioural problems (-2·44 [-4·22 to -0·67]; p=0·0070) than patients who had received early-parenteral nutrition, after adjusting for risk factors, and were no longer different from healthy controls for these outcomes.

INTERPRETATION

Omitting early parenteral nutrition use for critically ill children did not adversely affect long-term outcomes 4 years after randomisation and protected against emotional and behavioural problems, further supporting the deimplementation of early parenteral nutrition.

FUNDING

European Research Council, Methusalem, Flanders Institute for Science and Technology, Research Foundation Flanders, Sophia Foundation, Stichting Agis Zorginnovatie, Erasmus Trustfonds, and the European Society for Clinical Nutrition and Metabolism.

SUN-072 Age of Critically Ill Children at Time of Exposure to Early Parenteral Nutrition Determines Its Impact on Long-Term Physical and Cognitive Development

Background

The PEPaNIC RCT, which investigated critically ill children admitted to the pediatric intensive care unit, showed that early administration of parenteral nutrition (early PN) as compared with withholding PN for 1 week (late PN) negatively affected 6 neurocognitive functions assessed 2 years later (1). However, it is theoretically possible that age at time of exposure determines whether early PN has negative or positive impact on long-term physical and cognitive development, possibly resulting in a neutral outcome for the total study population. In this secondary analysis of the PEPaNIC RCT, we investigated whether age at exposure to early PN determined its 2 years developmental impact.

Methods

The 786 children who were evaluated 2 years after inclusion in the PEPaNIC RCT for health status, anthropometrics, executive functioning, emotional and behavioral problems, intelligence and visual motor integration were categorized for age at randomization (0–17 years). We defined 4 ±similarly sized age groups based on previously reported timing of cerebral maturation spurts: neonates ≤28 days old (n=121), infants 29 days to <11 months old (n=239), toddlers 11 months to <5 years old (n=223), children 5 years or older (n=203). For each outcome, interaction between the randomized intervention and age at randomization was assessed with a multivariable linear regression analysis adjusted for baseline risk factors. For the outcomes with an interaction p≤0.15, we subsequently compared the adjusted effect of early PN versus late PN within each age group.

Results

Interaction between randomization and age group was identified for weight, development of inhibitory control, flexibility, working memory, planning and organization, metacognition, total executive functioning and internalizing and total behavioral problems. In particular among infants 29 days to <11 months old, harm by early PN was observed for several neurocognitive functions [inhibitory control (p=0.008), flexibility (p=0.02), working memory (p=0.009), planning and organization (p=0.004), metacognition (p=0.008), total executive functioning (p=0.004), internalizing (p=0.005) and total behavioral problems (p=0.01)]. Among toddlers 11 months to <5 years old, neurocognitive harm by early PN was only observed for inhibitory control (p=0.003) and total executive functioning (p=0.02). In neonates ≤28 days old, early PN did not affect neurocognitive development whereas it increased weight (p=0.03) but not height. Among children 5 years or older, early PN only appeared to affect development of planning and organization in a positive manner (p=0.03).

Conclusion

Critically ill children who were exposed to early PN at an age between 29 days and 11 months were found to be most vulnerable for neurocognitive developmental harm evoked by early administration of PN, as assessed 2 years later.

1 Verstraete et al. Lancet Respir Med 2018

MON-LB012 Long-Term Developmental Impact of Withholding Parenteral Nutrition in Pediatric-ICU: A 4-Year Follow-Up of the Pepanic Randomized Controlled Trial

Aim: Between 2012-2015, the PEPaNIC randomized controlled trial, which included 1440 critically ill infants and children, showed that withholding parenteral nutrition during the first week in the pediatric intensive care unit (PICU) (late-PN), as compared with initiating supplemental PN early (early-PN), improved PICU outcomes (1) and improved neurocognitive development assessed 2 years later (2). The latter was explained by avoiding early-PN induced adversely altered DNA-methylation of 37 CpG sites (3). As a large number of patients were younger than 1 year of age at randomization and given that assessment of most neurocognitive domains is only possible from 4 years of age onwards, we performed a 4-year follow-up to determine the impact of late-PN versus early-PN on physical, neurocognitive, and emotional/behavioral development. This pre-planned, 4-year follow-up study of the 1440 PEPaNIC patients and of 369 matched healthy children was blinded for treatment allocation (ClinicalTrials.gov-NCT01536275). Methods: Studied clinical outcomes included anthropometrics, health status, parent/caregiver-reported executive functions, and emotional/behavioral problems, and clinical tests for intelligence, visual-motor integration, alertness, motor coordination and memory. Univariable and multivariable linear and logistic regression analyses adjusted for risk factors assessed the impact of late-PN versus early-PN on the outcomes and investigated a potential mediation role of the adversely altered DNA-methylation of 37 CpG sites previously shown to be evoked by late-PN as compared with early-PN (3). Results: Overall, at 4 years follow-up, patients (356 late-PN patients, 328 early-PN patients) could be tested neurocognitively. They revealed worse anthropometric, health status, neurocognitive and emotional/behavioral developmental outcomes than the healthy control children. Outcomes of late-PN patients were never worse than those of early-PN patients. In contrast, late-PN patients had fewer internalizing (P=0.042) and externalizing problems (P=0.046), and fewer total emotional/behavioral problems (P=0.007) than early-PN patients, which were normalized by late-PN. Avoiding the early-PN induced adversely altered DNA-methylation status of the 37 CpG sites statistically explained its impact on the behavioral outcomes. Conclusion: Four years after randomization to late-PN or early-PN in the PICU, late-PN did not show harm, and was found to protect against emotional/behavioral problems, with altered DNA-methylation as a potential biological mediator hereof. These data further support de-implementation of PN-use early during critical illness in infants and children. (1) Fivez et al. N Eng J Med 2016 (2) Verstraete et al. Lancet Respir Med 2019 (3) Guiza et al. Lancet Respir Med 2020 (in press)

Early Supplemental Parenteral Nutrition in Critically Ill Children: An Update

In critically ill children admitted to pediatric intensive care units (PICUs), enteral nutrition (EN) is often delayed due to gastrointestinal dysfunction or interrupted. Since a macronutrient deficit in these patients has been associated with adverse outcomes in observational studies, supplemental parenteral nutrition (PN) in PICUs has long been widely advised to meeting nutritional requirements. However, uncertainty of timing of initiation, optimal dose and composition of PN has led to a wide variation in previous guidelines and current clinical practices. The PEPaNIC (Early versus Late Parenteral Nutrition in the Pediatric ICU) randomized controlled trial recently showed that withholding PN in the first week in PICUs reduced incidence of new infections and accelerated recovery as compared with providing supplemental PN early (within 24 hours after PICU admission), irrespective of diagnosis, severity of illness, risk of malnutrition or age. The early withholding of amino acids in particular, which are powerful suppressors of intracellular quality control by autophagy, statistically explained this outcome benefit. Importantly, two years after PICU admission, not providing supplemental PN early in PICUs did not negatively affect mortality, growth or health status, and significantly improved neurocognitive development. These findings have an important impact on the recently issued guidelines for PN administration to critically ill children. In this review, we summarize the most recent literature that provides evidence on the implications for clinical practice with regard to the use of early supplemental PN in critically ill children.

Parity-induced changes in global gene expression in the human mammary gland

The protective effect of an early first full-term pregnancy in relation to breast cancer risk is well established, but the molecular and cell-specific changes in the human mammary gland involved remain unclear. To identify the molecular changes associated with pregnancy-induced differentiation, we analysed the global gene expression profiles of normal mammary tissues from both a parous and a nulliparous woman, using serial analysis of gene expression. This approach allowed us to identify sets of genes, known and unknown, that are differentially expressed in parous versus age-matched nulliparous mammary gland tissues. The normal mammary gland of a multiparous woman is characterized by several known differentiation markers such as casein kappa, casein beta, keratin 14, CCAAT/enhancer binding protein beta and delta and adipsin. Candidate genes involved in cytoarchitectural remodelling and growth inhibition with a potential role in pregnancy-induced protection against breast cancer were also observed. Several genes that are highly expressed in the nulliparous mammary gland and that are lost after pregnancy, encode for growth promoting, cytoskeletal and extracellular matrix proteins. One of these genes, the small breast epithelial mucin, is almost completely downregulated upon a first full-term pregnancy but is known to be expressed in more than 90% of invasive ductal carcinomas.

Protein biomarkers for breast cancer prevention

Protein biomarkers suitable for the prevention of breast cancer must be extremely sensitive, easily detectable and highly correlated with the disease. They should be expressed in the reversible phase of carcinogenesis. Among the large number of candidate tumour-associated proteins, those related to the oestrogen/chorionic gonadotropin/insulin pathway seem to be of most interest because these can be causally implicated. They presumably are the first to express differently and are open to hormonal treatments. The biomarkers that give information on membrane receptor-modulated signal transduction should be considered as well. Up to now, only tamoxifen has shown some preventive activity, suggesting that the oestrogen pathway is useful indeed. Fenretinide and recombinant human chorionic gonatotropin (hCG) are also promising. But the financial requirements and the very long assessment periods largely prevent current research. This is precisely why we badly need to give priority to molecular biology research, in particular in the protein compartment There is widespread belief that advanced proteomics together with increased informatics can provide specific combinations of disease-related expression profiles that could identify high-risk groups with much more reliability and allow us to monitor preventive strategies.