Abstract P3-07-03: PIK3CA mutations predict resistance to trastuzumab/pertuzumab and nab-paclitaxel in primary HER2-positive breast cancer – Massive parallel sequencing analysis of 293 pretherapeutic core biopsies of the GeparSepto study

Background: Phosphatidylinositol 3-kinase mutations (PIK3CA) are common in breast cancer (BC). Mutations are predominantly found in hot-spots located in the helical and kinase domains (exons 9 and 20). We recently demonstrated that PIK3CA mutations predict lower pathological complete response (pCR) to double blockade with trastuzumab/lapatinib in HER2+ve primary BC.

Methods: We evaluated PIK3CA mutations in 293/403 HER2+ve tumors of participants of the neoadjuvant GeparSepto (G7) study (Untch et al. SABCS 2014). The G7 study investigated the effect of exchanging paclitaxel for nab-paclitaxel prior to EC. All patients received trastuzumab and pertuzumab. The G7 study showed a significantly higher pCR rate in patients receiving nab-paclitaxel. HER2, hormone receptors (HR), Ki67 and tumor infiltrating lymphocytes (TILs) were centrally assessed prior to randomization. PIK3CA mutations in exons 9 and 20 were evaluated in formalin-fixed, paraffin embedded core biopsies taken before therapy using deep targeted massive parallel sequencing with a minimum coverage of 500 and a mean coverage of 6520 and 6346 per amplicon, (exon9 and exon 20). Only non-synonymous mutations in the coding region that were called at variant allele frequency ≥10% were taken into consideration. Only cases with a tumor cell content of ≥20% were included.

Results: In the G7 study, 396 patients with HER2+ve BC have been randomized from 06/2012 to 01/2014 and started treatment. From these 293 could be sequenced. Median age in the analyzed cohort was 49 years (range 22-75); most tumors were cT1-2 (89.9%); cN0 (54.4%); ductal invasive (88.7%), grade 3 (53.9%), HR+ve (69.6%), Ki67>20% (69.3%), LPBC-negative (83.2%). Overall, 22.2% of the tumors were found to have a PIK3CA mutation, 20.1% in HR+ve and 27.0% in HR-ve. Overall, the pCR rate was significantly lower in the PIK3CA mutant tumors compared to the wild type (wt) group (47.7% vs. 66.7%; p=0.009). This effect was seen both in the HR+ve (43.9% vs. 61.3%; p=0.052) and the HR-ve population (54.2% vs. 80.0%; p=0.029). There was also a significant difference in pCR according to PIK3CA mutation status dependant on the taxane. In the nab-paclitaxel group, pCR rates were significantly lower in patients with PIK3CA mutations compared to those without PIK3CA mutations (38.7% vs. 72.0%; p=0.001), whereas in the paclitaxel group, there was no significant difference between patients with and without a PIK3CA mutation (55.9% vs. 60.9%; p=0.690). The respective interaction could be demonstrated in univariate (p=0.039) as well as multivariate regression analysis (p=0.010) after adjusting for known baseline factors.

Conclusion: Patients with PIK3CA mutant HER2+ve BC have a significantly lower pCR rate compared to patients with wt tumors. In contrast to the results with double anti-HER2 blockade consisting of trastuzumab/lapatinib, the effect was evident irrespective of the HR status. In addition, PIK3CA mutation status was significantly associated with higher pCR following nab-paclitaxel.

The project has partly been funded within the EU-FP7 project RESPONSIFY No 278659 and the German Cancer Consortium (DKTK).

Citation Format: Loibl S, Budczies J, Weichert W, Furlanetto J, Stenzinger A, Pfarr N, von Minckwitz G, Jackisch C, Schneeweiss A, Fasching P, Schmatloch S, Aktas B, Nekljudova V, Weber K, Untch M, Denkert C. PIK3CA mutations predict resistance to trastuzumab/pertuzumab and nab-paclitaxel in primary HER2-positive breast cancer – Massive parallel sequencing analysis of 293 pretherapeutic core biopsies of the GeparSepto study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-03.

Detection of feline coronavirus in cerebrospinal fluid for diagnosis of feline infectious peritonitis in cats with and without neurological signs

OBJECTIVES

The objective of this study was to evaluate the sensitivity and specificity of a real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR) detecting feline coronavirus (FCoV) RNA in cerebrospinal fluid (CSF) of cats with and without neurological and/or ocular signs for the diagnosis of feline infectious peritonitis (FIP).

METHODS

This prospective case-control study included 34 cats. Nineteen cats had a definitive histopathological diagnosis of FIP (seven of these with neurological and/or ocular signs), and 15 cats had other diseases but similar clinical signs (three of these with neurological and/or ocular signs). Real-time RT-PCR was performed on the CSF of all cats, and sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) were calculated.

RESULTS

Real-time RT-PCR of CSF showed a specificity of 100% in diagnosing FIP, a sensitivity of 42.1%, a PPV of 100% and an NPV of 57.7%. The sensitivity of the real-time RT-PCR of CSF in cats with neurological and/or ocular signs was 85.7%.

CONCLUSIONS AND RELEVANCE

Although it is known that RT-PCR can give false positive results, especially if performed using serum or plasma, this real-time RT-PCR detecting FCoV RNA in CSF can be considered a reliable specific tool for the diagnosis of FIP. If only cats with neurological involvement are evaluated, the sensitivity of this real-time RT-PCR in CSF is also high.

HD DVD substrates for surface enhanced Raman spectroscopy analysis: fabrication, theoretical predictions and practical performance

Commercially available HD-DVD templates have been used to theoretically predict the occurrence of surface plasmons supermodes which improve the detection of surface enhanced Raman signals.

Meter-scale spark X-ray spectrum statistics

X-ray emission by sparks implies bremsstrahlung from a population of energetic electrons, but the details of this process remain a mystery. We present detailed statistical analysis of X-ray spectra detected by multiple detectors during sparks produced by 1 MV negative high-voltage pulses with 1 μs risetime. With over 900 shots, we statistically analyze the signals, assuming that the distribution of spark X-ray fluence behaves as a power law and that the energy spectrum of X-rays detectable after traversing ∼2 m of air and a thin aluminum shield is exponential. We then determine the parameters of those distributions by fitting cumulative distribution functions to the observations. The fit results match the observations very well if the mean of the exponential X-ray energy distribution is 86 ± 7 keV and the spark X-ray fluence power law distribution has index -1.29 ± 0.04 and spans at least 3 orders of magnitude in fluence.

Comparison of the prevalence of Mycoplasma species in dogs with and without respiratory disease

Aim of the study was to investigate the prevalence of Mycoplasma species in dogs with and without signs of respiratory disease. Bronchoalveolarlavage fluid (BALF) and pharyngeal swabs were collected from 29 dogs with respiratory diseases (RD) and 16 dogs without signs of RD that were euthanised because of other diseases. Samples were tested for Mycoplasma species by PCR and culture, and sequencing was performed in Mycoplasma species-positive BALF samples. Pharyngeal swabs were positive for Mycoplasma species by PCR in 91.7% of dogs with RD and 86.7% of dogs without signs of RD (p = 1.000); BALF samples were PCR-positive in 37.9% of dogs with RD and 18.8% of dogs without signs of RD (p = 0.194) Mycoplasmo culture of BALF was positive in 28.6% of dogs with RD and in 18.8% without signs of RD (p = 0.730). When culture and PCR were compared, there was no significant difference in the detection rate of Mycoplasma species (p = 0.658) Sequencing detected different Mycoplasma species. Out of these, however, Mycoplasma cynos was isolated from four dogs with RD. There is no significant difference in the prevalence of Mycoplasma species between dogs with RD and dogs without evidence of RD; however, Mycoplasma cynos seems to be associated with respiratory disease.

Detection of monoclonality in intestinal lymphoma with polymerase chain reaction for antigen receptor gene rearrangement analysis to differentiate from enteritis in dogs

The diagnosis of canine intestinal lymphoma by morphological examination is challenging, especially when endoscopic tissue specimens are used. The utility of detection of antigen receptor gene rearrangement by polymerase chain reaction (PARR) in canine lymphoma has been well established, but its usefulness to distinguish enteritis and intestinal lymphoma remains unclear. In this retrospective study we assessed clonality of 29 primary canine intestinal lymphoma, 14 enteritis and 15 healthy control cases by PARR analysis, using formalin-fixed, paraffin-embedded full-thickness tissue specimens. We could detect monoclonal rearrangements in 22 of 29 canine intestinal lymphomas [76%; 95% confidence interval (CI) 56-90%] and polyclonal rearrangements in all of the enteritis and healthy control cases (100%; CI 88-100%). We revealed a predominance of T-cell phenotype compared to B-cell phenotype (85%; CI 65-96% and 15%; CI 4-35%, respectively). We showed that PARR analysis contributes to differentiation of canine intestinal lymphoma from enteritis and to phenotyping of lymphomas.

[Efficacy of siRNA on feline leukemia virus replication in vitro]

Feline leukemia virus (FeLV) can lead to severe clinical signs in cats. Until now, there is no effective therapy for FeLV-infected cats. RNA interference-based antiviral therapy is a new concept. Specific small interfering RNA (siRNA) are designed complementary to the mRNA of a target region, and thus inhibit replication. Several studies have proven efficacy of siRNAs in inhibiting virus replication. The aim of this study was to evaluate the inhibitory potential of siRNAs against FeLV replication in vitro. siRNAs against the FeLV env gene and the host cell surface receptor (feTHTR1) which is used by FeLV-A for entry as well as siRNA that were not complementary to the FeLV or cat genome, were tested. Crandell feline kidney cells (CrFK cells) were transfected with FeLV-A/Glasgow-1. On day 13, infected cells were transfected with siRNAs. As control, cells were mock-transfected or treated with azidothymidine (AZT) (5 μg/ml). Culture supernatants were analyzed for FeLV RNA using quantitative real-time RT-PCR and for FeLV p27 by ELISA every 24 hours for five days. All siRNAs significantly reduced viral RNA and p27 production, starting after 48 hours. The fact that non-complementary siRNAs also inhibited virus replication may lead to the conclusion that unspecific mechanisms rather than specific binding lead to inhibition.

[Eating disorders and psychiatric day hospital treatment]

Eating disorders are complex pathologies characterised by the entanglement between physical and mental aspects and by their high impact on health. Studies on care models showed the need for other therapeutic modalities due to the complexity of treatments, the risk of recurrence after hospitalisation, as well as to the cost and duration of hospital stays. Day hospitals specific to these disorders have been created, albeit with very few studies. Even though the available studies tend to find good therapeutic efficacy, they are disparate, describing care centres that are rather different in their structure and theoretical approach, and factors of therapeutic efficacy are not always well described.

[Neurological diseases and suicide: from neurobiology to hopelessness]

Neurologic diseases expose at a high risk of suicidal behaviors and they constitute a privileged domain for exploring the heterogeneity of underlying mechanisms. They are in fact characterized by strictly biological injuries that may be involved in cerebral systems considered at the basis of neurobiological vulnerability for suicide. At the same time, they oblige a numberof existential topics to emerge, as the hopelessness in respect of several particularly severe conditions without an etiologic treatment. A clinical approach reserving an unconditional listening can prevent a suicidal attempt. Furthermore, it can illustrate the role of the liaison's psychiatrist, who tries to transform a hopelessness situation into a patient's personal questioning and try to be present when therapeutic action is not longer possible.

Decreased expression of cell proliferation-related genes in clonally derived skin fibroblasts from children with Silver-Russell syndrome is independent of the degree of 11p15 ICR1 hypomethylation

Background

The in vitro analysis of the hypomethylation of imprinting control region 1 (ICR1) within the IGF2/H19 locus is challenged by the mosaic distribution of the epimutation in tissues from children with Silver-Russell syndrome (SRS). To exclude mosaicism, clonal cultures of skin fibroblasts from four children with SRS and three controls were analyzed. Cell proliferation, IGF-II secretion, and IGF2 and H19 expression were measured, and a microarray expression analysis was performed.

Results

Single-cell expansion established severely ICR1 hypomethylated clones (SRShypo) and normomethylated clones (SRSnormo) from the patients and controls (Cnormo). IGF2 expression was below the detection limit of the quantitative real-time PCR (qRT-PCR) assay, whereas H19 expression was detectable, without differences between fibroblast clones. Cell count-related IGF-II release was comparable in SRShypo and Cnormo supernatants. Cell proliferation was diminished in SRShypo compared to Cnormo (p = 0.035). The microarray analysis revealed gene expression changes in SRS clones, predicting a decrease in cell proliferation and a delay in mitosis.

Conclusions

The analysis of severely ICR1 hypomethylated clonal fibroblasts did not reveal functional differences compared to normomethylated clones with respect to IGF2 and H19 expression. A difference compared to the clones from healthy individuals was present in the form of a lower proliferation rate, presumably due to impaired cell cycle progression.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-014-0038-0) contains supplementary material, which is available to authorized users.

Serum microRNA profiles in cats with hypertrophic cardiomyopathy

The role of microRNAs (miRNAs) in the pathogenesis of heart diseases of humans and rodents, as well as their diagnostic potential, has recently received much attention, but comparable studies for spontaneous disease models in the domestic cat are missing. Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats. The pathology is largely unknown, but is suspected to be influenced by genetic background. In this study, we examined the miRNA profiles in the serum of cats with stable congestive heart failure caused by HCM (n = 11) and healthy control cats (n = 12) using miRNA arrays. 965 out of 2026 miRNAs could be detected in at least six samples of either of the groups. Eleven mammalian miRNAs were differentially expressed between the groups with a fold change ≥ 1.6. Hierarchical cluster analysis resulted in distinct separation of the two groups. After correction for multiple testing (adjusted p < 0.05), a higher expression of miR-381-3p, miR-486-3p, miR-4751, miR-476c-3p, miR-5700, miR-513a-3p, and miR-320e in the HCM group was confirmed. Additionally, miR-1246 was found to be upregulated 3-fold in the HCM group using quantitative RT-PCR. Software analysis of the significantly regulated miRNAs revealed 49 mRNA targets involved in cardiac hypertrophy. Cats with primary HCM show a distinct miRNA profile that includes miRNAs that have already been shown to be differentially regulated in human patients and rodent models for cardiac disease. Studying HCM as a spontaneous cardiac disease of the cat may help to reveal additional pathophysiologic pathways.

Droplet based microfluidics: spectroscopic characterization of levofloxacin and its SERS detection

The determination of the absorption behavior of levofloxacin (levaquin) on the surface of silver nanoparticles and its determination in aqueous solution by droplet based microfluidics combined with surface enhanced Raman spectroscopy.

Micro-lightguide spectrophotometry (O2C®) as a predictor of intermediate outcome in patients with critical limb ischemia after percutaneous transluminal angioplasty (PTA)

AIM

Micro-lightguide spectrophotometry (O2C®) provides easily and rapidly measurable parameters of tissue microcirculation. The aim of this study was to assess whether micro-lightguide spectrophotometer (O2C®) based parameters of the tissue microcirculation can serve as predictors of ulcer healing. Furthermore, we tried to identify cut off values to forecast patient outcome and check other diagnostic meanings of individual O2C-parameters.

METHODS

Forty individuals, all suffering from critical limb ischemia and arterial or arteriovenous ulcers were retrospectively investigated concerning O2C®- and ankle/toe brachial index-measurements before and up to two times after percutaneous transluminal angioplasty (PTA). At a median follow-up of 7 (range 3 to 14) months after PTA the current peripheral arterial disease (PAD) status, ulcer healing, adverse cardiovascular events including death and endovascular or surgical treatments were noted.

RESULTS

We found in patients with healing wounds a significant increase in oxygen saturation (SO2, median 26.35±26.94%) compared to non-healers (-4.27±25.24%, P=0.006) as well as regarding blood flow (median 41.12±51.23AU vs. -9.46±24.01 AU, P=0.005). Additionally, the parameter rHb separated reliably between arterial and arteriovenous ulcers (P=0.024). In Cox regression models, increases after revascularisation of more than 6 % in SO2 (HRR=6.08, 95%CI 1.56-23.65, P=0.009) and flow decreases of less than 12 AU (HRR 4.95, 95%CI 1.42-17.31, P=0.012) were significantly associated with amputation-free survival.

CONCLUSION

The O2C®-parameters SO2 and flow provide prognostic information for ulcer healing as well as for amputation-free survival, and rHB adds information about a possible arterial or arteriovenous genesis of an ulcer.

Detection of feline Mycoplasma species in cats with feline asthma and chronic bronchitis

Little is known about the aetiology of inflammatory lower airway disease in cats. The aim of this study was to investigate the role of Mycoplasma species in cats with feline asthma (FA) and chronic bronchitis (CB). The study population consisted of 17 cats with FA/CB, and 14 sick cats without clinical and historical signs of respiratory disease, which were euthanased for various other reasons. Nasal swabs, nasal lavage and bronchoalveolar lavage fluid (BALF) samples were taken from patients from both groups. Mycoplasma species culture with modified Hayflick agar and Mycoplasma polymerase chain reaction (PCR) were performed on all samples followed by sequencing of all Mycoplasma species-positive samples for differentiation of subspecies. PCR testing detected significantly more Mycoplasma species-positive BALF samples than Mycoplasma culture (P = 0.021). When cats with oropharyngeal contamination were excluded from comparison, the numbers of Mycoplasma species-positive BALF samples in the group with FA/CB (6/17) and the control group (4/9) were not significantly different (P = 0.6924). While all nasal samples of the cats with FA/CB were negative for Mycoplasma organisms, five samples in the control group (P = 0.041) were positive on PCR. Sequencing revealed Mycoplasma felis in all PCR-positive samples. Mycoplasma species can be detected in the lower airways of cats with FA/CB, as well as in the BALF of sick cats without respiratory signs. Further studies are warranted to investigate the possibility that Mycoplasma species represent commensals of the lower respiratory tract of cats.

The effect of silver thickness on the enhancement of polymer based SERS substrates

We investigated silver-covered polymer based nanogratings as substrates for surface-enhanced Raman spectroscopy (SERS), in particular with respect to the thickness of the plasmonically active silver film. In order to obtain accurate geometrical input data for the simulation process, we inspected cross sections of the gratings prepared by breaking at cryogenic temperature. We noticed a strong dependence of the simulation results on geometrical variations of the structures. Measurements revealed that an increasing silver film thickness on top of the nanogratings leads to a blue shift of the plasmonic resonance, as predicted by numerical simulations, as well as to an increased field enhancement for an excitation at 488 nm. We found a clear deviation of the experimental data compared to the simulated results for very thin silver films due to an island-like growth at a silver thickness below 20 nm. In order to investigate the SERS activity. we carried out measurements with crystal violet as a model analyte at an excitation wavelength of 488 nm. The SERS enhancement increases up to a silver thickness of about 30 nm, whereas it remains nearly constant for thicker silver films.

IGF-I sensitivity in Silver-Russell syndrome with IGF2/H19 hypomethylation

BACKGROUND

Silver-Russell syndrome (SRS) is characterized by intrauterine and postnatal growth retardation, typical facial appearance and body asymmetry. The mechanism of growth retardation is unclear. 50% of the patients have a paternal chromosome 11 epimutation-DNA hypomethylation of the imprinting center region 1 (ICR1) of the insulin-like growth factor 2 (IGF2)/H19 locus. SRS children who carry such an epimutation have increased levels of IGF-I and IGFBP-3 in relation to their stature and body weight, suggesting IGF-I resistance. No IGF-I receptor (IGF-1R) defect has been discovered. Therefore, another mechanism, probably an IGF-I post-receptor signaling defect, might be present.

OBJECTIVE

The aim of this in-vitro study was to examine: 1) if IGF-I- and IGF-II-induced fibroblast growth is different in SRS children with IGF2/H19 hypomethylation compared to controls; and 2) whether there is IGF-I insensitivity in this subgroup of SRS children due to IGF-I post-receptor signaling defects.

DESIGN

Four SRS patients (two males, two females; 9.2 to 16.6 years of age) with an IGF2/H19 hypomethylation defect and three age-matched healthy controls were included in the in-vitro study. Cultivated skin fibroblasts from the patients and the healthy controls were used for the experiments. Proliferation rates of fibroblasts were measured in the presence or absence of recombinant human IGF-I and IGF-II using the commercially available 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) test. PI3K (phosphoinositide 3-kinase) assay and NF-κB transcription factor assay were performed using ELISA in order to estimate the IGF-I-stimulated Akt phosphorylation and IκB phosphorylation, respectively.

RESULTS

Fibroblasts from SRS patients and fibroblasts from control individuals showed a comparable potential to proliferate in serum-free medium when stimulated with IGFs. No significant differences were found between both groups concerning Akt phosphorylation and IκB phosphorylation rates.

CONCLUSIONS

The results of the in-vitro study do not support the hypothesis that IGF-I/IGF-II resistance is a major pathogenetic mechanism responsible for the growth failure in the subgroup of SRS children with IGF2/H19 hypomethylation.

A hundred patients with vertical rectus abdominis myocutaneous (VRAM) flap for pelvic reconstruction after total pelvic exenteration

PURPOSE

We analysed the outcomes of a series of 100 consecutive patients with anorectal cancer with neoadjuvant radiochemotherapy and abdominoperineal exstirpation or total pelvic exenteration, who received a transpelvic vertical rectus abdominis myocutaneous (VRAM) flap for pelvic, vaginal and/or perineal reconstruction and compare a cohort to patients without VRAM flaps.

METHODS

Within a 10-year period (2003-2013) in our institution 924 patients with rectal cancer stage y0 to y IV were surgically treated. Data of those 100 consecutive patients who received a transpelvic VRAM flap were collected and compared to patients without flaps.

RESULTS

In 100 consecutive patients with transpelvic VRAM flaps, major donor site complications occurred in 6 %, VRAM-specific perineal wound complications were observed in 11 % of the patients and overall 30-day mortality was 2 %.

CONCLUSIONS

The VRAM flap is a reliable and safe method for pelvic reconstruction in patients with advanced disease requiring pelvic exenteration and irradiation, with a relatively low rate of donor and recipient site complications. In this first study, to compare a large number of patients with VRAM flap reconstruction to patients without pelvic VRAM flap reconstruction, a clear advantage of simultaneous pelvic reconstruction is demonstrated.

[Laparoscopic surgery for colon cancer: quality requirements for (extended) right hemicolectomy]

The current S3 guidelines on the surgical treatment of colorectal cancer note that with a suitable patient selection and expertise of the surgeon the same oncological results can be achieved laparoscopically as with the open procedure. This requires that the same quality requirements have to be provided for both methods. The most important quality parameters of right sided (extended) hemicolectomy are central ligation of the supplying arteries (ileocolic artery, right branch of the middle colic artery and middle colic artery) flush to the central origin of the vessel (superior mesenteric artery or middle colic artery) and the sharp dissection of the mesocolon without any preparation tears. The photographic documentation of the fresh surgical specimens for categorizing the preparation quality as well as to determine the pedicle of the vessel can capture this quality well and is also currently the best surrogate parameter to evaluate the oncological quality of the operation. At present, there are still considerable widespread deficits not only with the laparoscopic approach but also in open surgery which must be urgently fixed.