Abstract PS5-12: Preliminary correlative analysis of clinical outcomes with PIK3CA mutation (mut) status from a phase I/Ib study of GDC-0077 in patients (pts) with hormone receptor-positive/HER2-negative metastatic breast cancer (HR+/HER2- mBC)

Background

Mutations in p110α, encoded by PIK3CA, are present in ~40% of HR+/HER2- BCs. GDC-0077, a PI3Kα-selective inhibitor and mutant PI3Kα degrader, elicits antitumor activity in PIK3CAmut preclinical models as a single agent and when combined with endocrine therapy (ET). New evidence suggests BCs harboring multiple PIK3CAmut exhibit increased signaling through the PI3K/AKT pathway and are more sensitive to PI3Kα inhibitors compared with BCs with a single PIK3CAmut. We report a preliminary analysis of PIK3CAmut status with clinical outcomes from an ongoing study of GDC-0077 alone or with ET (letrozole/fulvestrant) ± palbociclib (palbo) in pts with PIK3CAmut HR+/HER2- mBC (NCT03006172).

Methods

Detectable PIK3CAmut from local tumor tissue/blood-based assay or tumor tissue by cobas PIK3CA assay were required to enroll. Plasma-derived circulating tumor (ct) DNA was collected at baseline (BL), cycle 1 day 15 (C1D15), and C2D1 (in the cohort where GDC-0077 starts at C1D15) to detect PIK3CAmut. Paired tumor samples were analyzed for Ki67 and pAKT/pS6 expression by immunohistochemistry. Single vs multiple PIK3CAmut was correlated with the percentage of pharmacodynamic (PD) inhibition of Ki67/pAKT/pS6 expression; with the PIK3CAmut allele frequency ratio between BL and C1D15 or C2D1 (MAFr15); with best overall response (BOR, RECIST v1.1); and with time on treatment (TOT) in days. Statistical analyses: Kruskal-Wallis and Mann-Whitney-Wilcoxon for group and pairwise comparisons, respectively, and two-sample proportion testing for categorical comparisons.

Results

Data cutoff was 03/20/2020. PIK3CAmut were detected in 87/103 (84.5%) pts with BL ctDNA available for sequencing. Multiple PIK3CAmut were detected in 21/87 (24.1%) BL ctDNA samples: 9 from pts treated with single-agent GDC-0077; 8 from pts treated with GDC-0077 + letrozole/fulvestrant; and 4 from pts treated with GDC-0077 + letrozole/fulvestrant + palbo. The median number of lines of prior therapy for metastatic disease was not different between pts with multiple (3.0 lines) vs single (2.5 lines) PIK3CAmut detected at BL (p = 0.205). Median percentage inhibition of Ki67/pAKT/pS6 expression was greater in pts with multiple (-65.8, -70.3, -66.8%, respectively) vs single (-42.1, -34.1, -29.5%) PIK3CAmut detected at BL (p = 0.095, 0.002, 0.056). Median MAFr15 was lower in pts with multiple (MAFr15 0.01) vs single PIK3CAmut (MAFr15 0.15) detected at BL (p = 0.004). Of 73 pts with both BL ctDNA-detected PIK3CAmut and BOR data, 16/16 (100%) with multiple PIK3CAmut experienced BOR of partial response (PR) or stable disease (SD) while 42/57 (73.7%) with single PIK3CAmut experienced BOR of PR or SD (p = 0.051). No pts with multiple PIK3CAmut detected experienced a BOR of progressive disease. Median TOT was greater in pts with multiple PIK3CAmut (196 days) vs single PIK3CAmut (140.5 days) detected at BL, but this was not significant (p = 0.1804).

Conclusions

The fraction of pts in which multiple PIK3CAmut were identified from BL ctDNA in this HR+/HER2- mBC dataset (24.1%) was slightly higher than reported elsewhere. This may be due to the method of detection (blood vs tissue) and/or the definition of multiple PIK3CAmut used. Pts in which multiple PIK3CAmut were detected by ctDNA exhibited greater depth of PD biomarker inhibition in tumors and experienced PR/SD more often compared with pts in which only one PIK3CAmut was detected. However, no significant associations were observed with the number of prior lines of therapy for metastatic disease or TOT. The dataset is currently too small to assess the impact of different treatment regimens in this study but will be re-evaluated as the data mature.

Citation Format: Komal Jhaveri, Dejan Juric, Andrea Varga, Nicolas Turner, Peter Schmid, Cristina Saura, Mafalda Oliveira, Ian E Krop, Kevin Kalinsky, Antoine Italiano, Erika Hamilton, Valentina Gambardella, Andrés Cervantes, Philippe L Bedard, Bonnie P Liu, Jessica W Chen, Junko Aimi, Stephanie Royer-Joo, Jennifer L Schutzman, Katherine E Hutchinson. Preliminary correlative analysis of clinical outcomes with PIK3CA mutation (mut) status from a phase I/Ib study of GDC-0077 in patients (pts) with hormone receptor-positive/HER2-negative metastatic breast cancer (HR+/HER2- mBC) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-12.

[The relationship between mental stimulation level of life events and suicide attempt of rural residents in Shandong Province]

Objective: To explore the relationship between the level of mental stimulation and the suicide attempts of rural residents in Shandong Province. Methods: A 1:1 matched case-control study was designed to collect 1 200 cases from a survey of three suicide attempts in rural areas of Shandong Province. Controls were selected according to the following matched factors: age difference within 3 years, same gender, same village or neighboring village, no blood relationship, no suicide history. The basic characteristics of all subjects were collected through the questionnaire, and the level of mental stimulation of life events was measured. Multivariate conditional logistic regression model was used to analyze the relationship between the level of mental stimulation of life events and suicide attempts. Results: The mean age of the case group and the control group was both (36.6±0.3) years old, and 35.8% (430/1 200) were males in each group. The low-medium level of mental stimulation of negative life events in the case group was 16.7% (200/1 200) and 61.7% (740/1 200), respectively, which was higher than that in the control group, about 2.5% (30/1 200) and 29.3% (352/1 200) (all P values <0.05), respectively. A total of 11.1% (133/1 200) of the case group had positive life events, which was lower than that of the control group [16.8% (201/1 200)] (all P values<0.05). Multivariate logistic regression model analysis showed that after the adjustment of gender, age, place of residence, education level, marital status, occupation, family income, somatic disease, mental disorders, family history of suicide, and opposite life events, the low-medium and high level of mental stimulation of negative life events were risk factors for suicide attempts, with OR (95%CI) as 5.88 (4.53-7.64) and 13.94 (8.15-23.86), respectively. Mental stimulation of positive life events was protective factor of suicide attempts, with OR (95%CI) as 0.58 (0.41-0.82). Conclusion: Mental stimulation of negative and positive life events were risk and protective factors for suicide attempts.

A Practical Review of Functional MRI Anatomy of the Language and Motor Systems

Functional MR imaging is being performed with increasing frequency in the typical neuroradiology practice; however, many readers of these studies have only a limited knowledge of the functional anatomy of the brain. This text will delineate the locations, anatomic boundaries, and functions of the cortical regions of the brain most commonly encountered in clinical practice-specifically, the regions involved in movement and language.

Abstract 1837: Comprehensive RNA-seq transcriptome interrogation of paired hepatocellular carcinoma and cirrhosis tissues revealed significant molecular features of disease evolution and modulation of tumor immunity

First 2 authors contributed equally

Hepatocellular carcinoma (HCC) is the second most common cause of death from cancer worldwide with extremely poor prognosis. HCC is known to be closely associated with liver injury-induced cirrhosis caused by various etiologies, including HBV infection. The prolonged timeline and heterogeneous nature of HCC adds complexity to dissecting the biology of this disease in humans. While Sorafenib is approved for the first-line treatment of metastatic HCC, most patients rapidly progress on treatment with Sorafenib. Consequently, alternative therapeutic options for HCC are much needed. The identification of molecular subtypes and reliable biomarkers associated with disease evolution is critical in facilitating development of new therapeutic agents in HCC.

To understand the manifestation of early molecular events in HCC disease progression in human, we analyzed genome-wide RNA-seq data derived from 100 paired samples consisting of HCC tumors (most with 60-80% tumor content) and adjacent cirrhotic tissues from early stage patients (TNM system: T1N0M0, T2N0M0, and T3N0M0; similar to BCLC stage A and B). Differential expression analysis revealed a cluster of genes that significantly differentiated HCC from cirrhotic tissues and illustrated a widespread deregulation of cell cycle machinery modulated by probable molecular abnormalities represented by Polo-Like Kinase, Checkpoint kinases, G2/M DNA damage checkpoint regulation, DNA damage-induced 14-3-3σ signaling, ATM signaling, and estrogen-mediated S-phase entry. Prominent down-regulation of FXR/LXR/RXR activation was also observed in HCC tumors. Strikingly, the unsupervised hierarchical clustering of both cirrhotic and HCC tissues revealed 3 groups of genes with mRNA expression closely correlating with disease progression stage-wise from cirrhosis to T1, T2, and T3 stages. Specifically, we made a novel observation illustrating the stage-wise activation of Wnt signaling pathway, but de-activation of MAPK pathway. Upon in-depth analysis, our data also suggests that as HCC progresses, translation machinery and embryonic morphogenesis are stimulated, while angiogenesis, negative regulation of apoptosis, and mesenchymal cell differentiation are possibly impinged. In addition, we found that components of processes crucial for activating immune response appear to be impaired as disease progresses from cirrhosis to stage T3. To confirm the aforementioned finding through focused assessment of immune-microenvironment by gene expression, we utilized Fluidigm platform and corroborated the down-regulation of effector T cell signature.

In conclusion, data presented provides a holistic depiction of evolution of HCC and the associated tumor immunity, thus paving a way for future detailed subtyping and therapeutics discovery.

Citation Format: Bonnie P. Liu, Kwame Okrah, Jeff Cheng, Maipelo Motlhabi, Charlie Sun, Teiko Sumiyoshi, Shoji Ikeda, Hartmut Koeppen, Zineb Mounir, Craig Cummings, Nadia Haque, Garret Hampton, Lukas Amler, Mark Lackner, Shih-Min A. Huang. Comprehensive RNA-seq transcriptome interrogation of paired hepatocellular carcinoma and cirrhosis tissues revealed significant molecular features of disease evolution and modulation of tumor immunity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1837.

Posterior glottic stenosis with a calcified interarytenoid scar band: CT and laryngoscopic correlation

A 52-year-old man with burn injuries and prolonged intubation developed PGS with hoarseness, dyspnea, and bilateral vocal cord immobility. On CT, a calcified interarytenoid scar band was identified, corresponding to an interarytenoid scar on laryngoscopy. Endoscopic laser lysis of the calcified scar band relieved the symptoms. We present laryngoscopic and CT findings of PGS with interarytenoid calcification along with the postlysis findings. The classification, clinical findings, imaging, and management of PGS are reviewed.

Percutaneous transosseous translaminar approach for thecal sac access in advanced ankylosing spondylitis with instrumented posterior spinal fusion

A novel transosseous approach for percutaneous access of the lumbar subarachnoid space is described in a patient with advanced ankylosing spondylitis (AS) and instrumented spinal fusion who presented for myelography. Use of a coaxial threaded bone biopsy system to provide transosseous access to the thecal sac, imaging findings, and outcome are discussed. This technique provided access to an otherwise inaccessible subarachnoid space and is an alternative approach in the setting of advanced AS or posterior spinal fusion.

Semaphorin-mediated axonal guidance via Rho-related G proteins

For many growing axons, interaction with an extracelluar Semaphorin signal leads to growth cone collapse and axon repulsion. Semaphorin receptors composed of Neuropilins and Plexins transduce extracellular cues into changes in the growth cone actin cytoskeleton. The data implicating Rho family G proteins in Semaphorin signaling and in other axon guidance events are considered here. Recent work makes it clear that Rac1 is required for this process. In particular, there is intriguing new evidence that the Plexin receptors communicate directly with members of the Rho family GTPases, although uncertainties remain concerning how Plexins alter Rac1 function. The CRMP (collapsin response mediator protein) family is also required for Plexin-based Semaphorin signaling, and new data demonstrate direct links to Rho and Rac1-based signaling.

Vav2 activates Rac1, Cdc42, and RhoA downstream from growth factor receptors but not beta1 integrins

The Rho family of GTPases plays a major role in the organization of the actin cytoskeleton. These G proteins are activated by guanine nucleotide exchange factors that stimulate the exchange of bound GDP for GTP. In their GTP-bound state, these G proteins interact with downstream effectors. Vav2 is an exchange factor for Rho family GTPases. It is a ubiquitously expressed homologue of Vav1, and like Vav1, it has previously been shown to be activated by tyrosine phosphorylation. Because Vav1 becomes tyrosine phosphorylated and activated following integrin engagement in hematopoietic cells, we investigated the tyrosine phosphorylation of Vav2 in response to integrin-mediated adhesion in fibroblasts and epithelial cells. However, no tyrosine phosphorylation of Vav2 was detected in response to integrin engagement. In contrast, treating cells with either epidermal growth factor or platelet-derived growth factor stimulated tyrosine phosphorylation of Vav2. We have examined the effects of overexpressing either wild-type or amino-terminally truncated (constitutively active) forms of Vav2 as fusion proteins with green fluorescent protein. Overexpression of either wild-type or constitutively active Vav2 resulted in prominent membrane ruffles and enhanced stress fibers. These cells revealed elevated rates of cell migration that were inhibited by expression of dominant negative forms of Rac1 and Cdc42. Using a binding assay to measure the activity of Rac1, Cdc42, and RhoA, we found that overexpression of Vav2 resulted in increased activity of each of these G proteins. Expression of a carboxy-terminal fragment of Vav2 decreased the elevation of Rac1 activity induced by epidermal growth factor, consistent with Vav2 mediating activation of Rac1 downstream from growth factor receptors.

Microtubule growth activates Rac1 to promote lamellipodial protrusion in fibroblasts

Microtubules are involved in actin-based protrusion at the leading-edge lamellipodia of migrating fibroblasts. Here we show that the growth of microtubules induced in fibroblasts by removal of the microtubule destabilizer nocodazole activates Rac1 GTPase, leading to the polymerization of actin in lamellipodial protrusions. Lamellipodial protrusions are also activated by the rapid growth of a disorganized array of very short microtubules induced by the microtubule-stabilizing drug taxol. Thus, neither microtubule shortening nor long-range microtubule-based intracellular transport is required for activating protrusion. We suggest that the growth phase of microtubule dynamic instability at leading-edge lamellipodia locally activates Rac1 to drive actin polymerization and lamellipodial protrusion required for cell migration.

Microtubule depolymerization induces stress fibers, focal adhesions, and DNA synthesis via the GTP-binding protein Rho

Microtubule depolymerization has multiple consequences that include actin stress fiber and focal adhesion assembly, increased tyrosine phosphorylation and DNA synthesis. Similar effects induced by serum, or agents such as lysophosphatidic acid, have previously been shown to be mediated by the GTP-binding protein Rho. We have investigated whether the effects of microtubule depolymerization are similarly mediated by Rho and show that they are blocked by the specific Rho inhibitor, C3 transferase. Because microtubule depolymerization induces these effects in quiescent cells, in which Rho is largely inactive, we conclude that microtubule depolymerization leads to activation of Rho. The activation of Rho in response to microtubule depolymerization and the consequent stimulation of contractility suggest a mechanism by which microtubules may regulate microfilament function in various motile phenomena. These range from growth cone extension to the development of the contractile ring during cytokinesis, in which there are interactions between the microtubule and microfilament systems.

Clinical evidence of genetic anticipation in adult-onset idiopathic dystonia

Idiopathic dystonia occurs in both hereditary and sporadic forms. In this report, we studied the age of onset and family history of 260 patients (probands) with idiopathic adult-onset dystonia (IAD), cranial or cervical. The mean age at onset of these patients was (45.71 +/- 15.85) years. Forty-nine probands had a positive family history of dystonia or tremor in first- and second-degree relatives, and 7 had affected siblings only. The significance of tremor as a part of clinical manifestation of dystonia was evidenced by a high frequency of postural or action tremor in patients and relatives. Retrospectively, we examined the age of onset of dystonia (cervical or cranial) on successive generations in 49 families. Age of onset of clinical symptoms was earlier, by an average of 21.25 years, in the second generation than in the first generation. The mean age at onset of affected family members differed significantly between successive generations in these 49 families (p = 1.11 x 10(-8)). Our results suggest a tendency for earlier onset of dystonia and worsening of disease phenotype in succeeding generations in the same family. These findings are most compatible with genetic anticipation and suggest that an unstable trinucleotide repeat is most likely involved in adult-onset primary cranial or cervical dystonia. In addition, tremor as an integral part of dystonia needs further evaluation by molecular genetic studies.

[Effects of combined therapy of traditional Chinese and Western medicine on C-reactive protein in post-debridement patients]

Closely monitoring whether the secondary infection in the patients of post-debridement occurred or not and appropriately treating these patients were the important ways to reduce the incidence of infection. Through estimating the level of the serum C-reactive protein (CRP) as the monitoring index of infection, dynamically observed the effect of the combined traditional Chinese and Western medicine therapy (TCM-WM) on CRP after debridement, as was compared with the effect of the Western medicine therapy (WM) group in which only the WM was administrated. The result showed that the levels of CRP decreased in both TCM-WM and WM group on 4th day after the operation, but the level of CRP in former group was lower than that in latter one, the difference was very significant (P < 0.001). So that, it was assumed that TCM-WM significantly excelled the WM on affecting the level of CRP and reducing the incidence of infection. It was suggested that CRP could be used as an effective and objective index to determine whether the secondary infection has happened and to assess the efficacy of some drugs.