Abstract P4-04-03: PIK3CA mutations in breast tumor specimens in a cohort (n=791) of a multicentric study and associations to known prognostic factors and survival data

Introduction:

The PI3K/AKT/mTOR signalling pathway plays an important role in cellular processes like proliferation, apoptosis, survival and adhesion of tumor cells. It is one oft the most deregulated pathways in cancer.

In up to 30% of breast cancers, dysregulation of this pathway is reported, resulting from mutations in the PIK3CA gene that encodes the catalytic subunit (p110a). Hotspots of mutations, comprising 86 % of all observed PIK3CA-mutations, were described in exon 9 (helical domain, E542K, G > A; E545K, G > A) and exon 20 (kinase domain, H1047R, A > G). Prevalence and the prognostic impact of the PIK3CA mutations as well as the predictive value with regard to endocrine therapy are controversially discussed.

In this study we describe the prevalence of the three most frequent PIK3CA mutations in a consecutive cohort of breast cancer patients and its association to tumor characteristics, to known prognostic factors and survival data.

Methods:

The cohort consists of 1,047 patients who were newly diagnosed for non-metastatic breast cancer in one of 6 German breast centres from 2009 to 2011 and who were registered within the prospective PiA-study (Prognostic assessment in routine Application, NCT 01592825). DNA of 806 fresh frozen tumors were available for analyzation by qPCR (exon 9: C 763 and C760; exon 20: C 775).

Associations between the PIK3CA mutation status and clinical, pathological parameters were evaluated using binary logistic regression model. Survival probabilities were estimated by Kaplan-Meier-method, Log-Rank-Test and Breslow-Test. Recurrence free interval (RFI) was defined according to STEEP criteria.

Results:

Mutation status for the three most common PIK3CA mutations was available for 791 tumors. The mutation rate was 29.2%. Only two tumors harbored two mutations (C 765, C 763). Tumors with a PIK3CA mutation were significantly more frequent in HR positive tumors (32%; p=0,001), in HER2 negative tumors (31%, p=0,010) and in tumors with low or intermediate histological grade (39%; 32% resp., each p<0,001). In triple negative tumors, PIK3CA mutations were found in 13%. There was no significant association to age, menopausal status, tumor size, nodal status and uPA/PAI-1 status.

Tumors with a PIK3CA mutation showed a slightly better recurrence-free interval (93.6%, CI 93.2-94.01 vs. 90.3%, CI 89.9-90.7). We found a prognostic impact on RFI after 5 ys F/U in patients with HR-negative tumors (93% vs 71%) and those with TNBC (100% vs. 70%).

Conclusion:

PIK3CA mutations occur frequently in breast cancer tumors. We found a prognostic impact only in patients with HR-negative and TNBC tumors.

This data adds important information to the heterogeneous results of other previously published patient cohorts. In summary in our study, tumors that harbour a mutation of the PIK3CA-gene, were associated to prognostically more favorable factors and a better recurrence-free intervall.

Citation Format: Reinhardt K, Thomssen C, Volker H, Tilmann L, Christoph U, Susanne P, Jutta J, Joerg B, Edith W, Karl-Friedrich B, Eva Johanna K, Martina V. PIK3CA mutations in breast tumor specimens in a cohort (n=791) of a multicentric study and associations to known prognostic factors and survival data [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-03.

Heritability, evolvability, phenotypic plasticity and temporal variation in sperm-competition success of Drosophila melanogaster

Sperm-competition success (SCS) is seen as centrally important for evolutionary change: superior fathers sire superior sons and thereby inherit the traits that make them superior. Additional hypotheses, that phenotypic plasticity in SCS and sperm ageing explain variation in paternity, are less considered. Even though various alleles have individually been shown to be correlated with variation in SCS, few studies have addressed the heritability, or evolvability, of overall SCS. Those studies that have addressed found low or no heritability and have not examined evolvability. They have further not excluded phenotypic plasticity, and temporal effects on SCS, despite their known dramatic effects on sperm function. In Drosophila melanogaster, we found that both standard components of sperm competition, sperm defence and sperm offence, showed nonsignificant heritability across several offspring cohorts. Instead, our analysis revealed, for the first time, the existence of phenotypic plasticity in SCS across an extreme environment (5% CO2 ), and an influence of sperm ageing. Evolvability of SCS was substantial for sperm defence but weak for sperm offence. Our results suggest that the paradigm of explaining evolution by sperm competition is more complex and will benefit from further experimental work on the heritability or evolvability of SCS, measuring phenotypic plasticity, and separating the effects of sperm competition and sperm ageing.

GATA1s induces hyperproliferation of eosinophil precursors in Down syndrome transient leukemia

Transient leukemia (TL) is evident in 5–10% of all neonates with Down syndrome (DS) and associated with N-terminal truncating GATA1-mutations (GATA1s). Here we report that TL cell clones generate abundant eosinophils in a substantial fraction of patients. Sorted eosinophils from patients with TL and eosinophilia carried the same GATA1s-mutation as sorted TL-blasts, consistent with their clonal origin. TL-blasts exhibited a genetic program characteristic of eosinophils and differentiated along the eosinophil lineage in vitro. Similarly, ectopic expression of Gata1s, but not Gata1, in wild-type CD34⁺-hematopoietic stem and progenitor cells induced hyperproliferation of eosinophil promyelocytes in vitro. While GATA1s retained the function of GATA1 to induce eosinophil genes by occupying their promoter regions, GATA1s was impaired in its ability to repress oncogenic MYC and the pro-proliferative E2F transcription network. ChIP-seq indicated reduced GATA1s occupancy at the MYC promoter. Knockdown of MYC, or the obligate E2F-cooperation partner DP1, rescued the GATA1s-induced hyperproliferative phenotype. In agreement, terminal eosinophil maturation was blocked in Gata1^Δe2 knockin mice, exclusively expressing Gata1s, leading to accumulation of eosinophil precursors in blood and bone marrow. These data suggest a direct relationship between the N-terminal truncating mutations of GATA1 and clonal eosinophilia in DS patients.

[GATA1-mutation associated leukemia in children with trisomy 21 mosaic]

Mutations of the hematopoietic transcription factor GATA1 (GATA1s) are pathognomonic in newborn with transient leukemia and children with Down syndrome and myeloid leukemia (ML-DS). Both TL and ML-DS can also occur in children with trisomy 21 mosaic.Between 2002 and 2011, 15 newborns and infants were diagnosed with DS mosaic. 9 of them presented with TL and 8 children suffered from ML-DS; 2 of them with a history of TL. In children without stigmata the special morphology and immunophenotype of blasts triggered the screening for GATA1 mutation and trisomy 21 mosaic.All newborns with TL achieved complete remission (CR). Due to clinical symptoms caused by the leukemic blasts, in 3 children low-dose cytarabine was applied. 1 patient died due to cardiac defect. In all patients GATA 1 s was confirmed. 6 children with ML-DS were initially treated according the AML-BFM protocol. After ML-DS was confirmed, therapy was continued with the intensity reduced schedule according to the ML-DS 2006 protocol. All children are still in CR (follow-up 1.8-7 years, median 2.7 yrs). 2 children with unknown trisomy 21 mosaic were diagnosed as acute megakaryoblastic leukemia (AMKL) and treated according the high risk arm of the AML-BFM 2004 including allogeneic stem cell transplantation in one child). GATA1 mutation was identified retrospectively. Both children are alive in CR.GATA1s associated leukemia has to be excluded in all young children with AMKL (<5 years old) to prevent overtreatment. Treatment with reduced intensity seems sufficient in children trisomy 21 mosaic and ML-DS.

[Interhospital transport of intensive care patients in Lower Saxony : statewide need-based and effective management]

BACKGROUND

Since 2007 interhospital transport of intensive care patients in Lower Saxony appertains to the performance requirements of emergency medical services. Against this background the Working Group for Evaluation of Intensive Care Transport (Arbeitsgemeinschaft Evaluation Intensivverlegung) was established. This group formulated standardized definitions for the requirements of intensive care transport vehicles and a federal statewide monitoring of intensive care transport was implemented to analyze if simultaneously on-call intensive care transport systems (intensive care helicopter and ground based mobile intensive care units) can be deployed need-based and efficiently.

METHODS

A prospective follow-up study and evaluation of intensive care transport in Lower Saxony between April 1(st) 2008 and July 31(st) 2010 was carried out.

RESULTS

A total of 6,779 data records were evaluated in this study of which 4,941 (72.9%) missions were located in Lower Saxony, 2,928 (43.2%) missions were carried out by helicopters and 3,851 (56.8%) by ground based mobile intensive care units. The mean duration of a mission was 3 h 59min±2 h 25 min, 4 h 39 min±2 h 23 min by ground based mobile intensive care units and 2 h 21 in±30 min by helicopter units. All systems proved to be feasible for intensive care transport. The degree of urgency was estimated correctly in 94.8% of the evaluated missions and 58.0% of the transfers could not be deployed. In 76.8% patients were transferred to hospitals with a higher level of medical care, 51.7% of patients were transferred for intensive care therapy and 40.4% for an operation/intervention. Of the patients 38.2% required mechanical ventilation and in 48.3% invasive monitoring was carried out.

CONCLUSION

Interhospital transfer of intensive care patients can be carried out need-based with a limited number of intensive care transport vehicles if the missions are deployed effectively by standardized disposition in accordance with performance requirements.

Neuromyelitis optica and NMO-IgG in European pediatric patients

OBJECTIVE

Neuromyelitis optica (NMO) is currently considered a severe relapsing CNS demyelinating disorder that is associated with aquaporin-4 immunoglobulin G (NMO-IgG) while in earlier reports of NMO in childhood it has been described as a benign and monophasic disorder. This study was performed to analyze the prevalence and the clinical course of NMO in a European pediatric cohort of patients with demyelinating CNS disorders.

METHODS

A cohort study was performed evaluating 118 pediatric patients presenting at the Center for Multiple Sclerosis in Childhood and Adolescents, Göttingen, Germany, with demyelinating CNS disorders between 2000 and 2009. In all patients, NMO-IgG status was determined.

RESULTS

The majority of patients (94%) were diagnosed with remitting recurrent multiple sclerosis. Six patients fulfilled the clinical criteria for NMO but only 1 was seropositive for NMO-IgG. This patient had a severe relapsing course in contrast to the seronegative patients who showed a mild and in the majority of cases monophasic course.

CONCLUSIONS

The diagnostic criteria clearly distinguished the patients with NMO from patients with other demyelinating CNS disorders. In the European pediatric population, NMO is very rare and in the majority of patients not associated with NMO-IgG. These seronegative cases have a benign and predominantly monophasic course and therefore do not need the immunosuppressant therapy that is recommended for NMO in the recent literature.

Estimating the feeding rate of the bedbug Cimex lectularius in an infested room: an inexpensive method and a case study

The common bedbug, Cimex lectularius L. (Hemiptera: Cimicidae), is a globally re-emerging pest that is playing an increasing role in legal disputes and compensation claims as a result of its unpleasant feeding activity. However, there is little information about the feeding frequency of bedbugs outside controlled laboratory cultures. Here, we present a simple method of estimating the average time since the last bloodmeal of individual female bedbugs in a single sampling event, applicable to a single bedbug harbourage or an entire room. Using the temperature-dependent rate of decrease in the abdomen size of the bedbug after a bloodmeal, we found that, in a highly infested room kept at a constant temperature of 26 degrees C, females fed every 2.5 days on average. Our method corrects for variations in body size across different populations and determines the shrinkage that occurs when individuals are preserved in ethanol. This method should, therefore, be widely applicable. It is cheap, rapid and, if coupled with information on the total number of bedbugs present in a room, allows for the estimation of the minimum number of times persons lodging in a room have been bitten by bedbugs. This method can also be used to calculate the feeding rate of other blood-sucking insects on their hosts. The sex ratio in the infestation was female-biased. Finally, our case study suggests that individual female bedbugs within a harbourage do not seem to feed at a regular rate, but tend to synchronize feeding patterns.

Novel CLN8 mutations confirm the clinical and ethnic diversity of late infantile neuronal ceroid lipofuscinosis

The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited lysosomal storage diseases and the prototype of childhood onset neurodegenerative disorders. To date, 10 NCL entities (CLN1-CLN10) are known and characterized by accumulation of autofluorescent storage material, age of onset and clinical symptoms. CLN8 was first identified as the causative gene for a late-onset form with progressive epilepsy and mental retardation in Finnish patients. In addition, CLN8 phenotypes were described in Turkish, Israeli and Italian patients with a more rapid progression of visual loss, epilepsy, ataxia and mental decline. Here, we report the first mutations in German (c.611G>T) and Pakistani (c.709G>A) patients. Our findings confirm previous assumptions that the CLN8 variant can occur in many ethnic groups. So far, large CLN gene deletions are only known for the CLN3 gene. Here, we also describe a novel, large CLN8 gene deletion c.544-2566_590del2613 in a Turkish family with a slightly more severe phenotype. Our data indicate that patients with clinical signs of late infantile NCL and characteristic ultrastructural inclusions should also be screened for CLN8 mutations independent of their ethnic origin.

Unilateral dilation of virchow-robin spaces in early childhood

Observations of extreme unilateral widening of Virchow-Robin spaces (VRS) are rare and hitherto confined to adult, mainly old-aged patients. Magnetic resonance imaging (MRI) was performed in two unrelated boys aged 3 years with developmental coordination disorders. In one of these patients, follow-up MRI and diffusion tensor imaging (DTI) were carried out 5 years later. In both boys, MRI incidentally revealed numerous intracerebral cysts strictly confined to one hemisphere. Localization, size, shape, and signal isointensity to cerebrospinal fluid indicated unilateral marked widening of VRS. In one patient, follow-up investigation after 5 years showed unchanged dilation of VRS on MRI, but mild facial hemihypertrophy, ipsilateral to the widened VRS. DTI indicated displacement rather than disruption of fiber tracks adjacent to the dilated VRS. Unilateral widening of VRS may be detected fortuitously on neuroimaging already in early childhood.