Predictive modelling of response to neoadjuvant therapy in HER2+ breast cancer

HER2-positive (HER2+) breast cancer accounts for 20-25% of all breast cancers. Predictive biomarkers of neoadjuvant therapy response are needed to better identify patients with early stage disease who may benefit from tailored treatments in the adjuvant setting. As part of the TCHL phase-II clinical trial (ICORG10-05/NCT01485926) whole exome DNA sequencing was carried out on normal-tumour pairs collected from 22 patients. Here we report predictive modelling of neoadjuvant therapy response using clinicopathological and genomic features of pre-treatment tumour biopsies identified age, estrogen receptor (ER) status and level of immune cell infiltration may together be important for predicting response. Clonal evolution analysis of longitudinally collected tumour samples show subclonal diversity and dynamics are evident with potential therapy resistant subclones detected. The sources of greater pre-treatment immunogenicity associated with a pathological complete response is largely unexplored in HER2+ tumours. However, here we point to the possibility of APOBEC associated mutagenesis, specifically in the ER-neg/HER2+ subtype as a potential mediator of this immunogenic phenotype.

Abstract 5787: Modelling the spatial heterogeneity of CD45-positive tumor infiltrating lymphocytes in early-stage, estrogen receptor-positive breast cancer

The frequency of lymphocytes infiltrating tumors is a known prognostic in estrogen receptor (ER) negative cancers. ER+ disease is putatively believed to be immune cold, however, there exists a subset of ER+ tumors with high immune infiltrate and with a significant spatial heterogeneity. The clinic impact of such infiltrate - especially between the Oncotype Dx Recurrence Score risk categories - remains unclear. Moreover, the distribution of tumor and stromal tissues, while noted as significantly heterogenous, is still ill-defined and not yet clinically used prognostically, despite evidence to support its utility. Using a cohort (n=450) of serial sections taken from early-stage, ER+/HER2- breast tumors of the Irish arm of the TAILORx clinical trial, we aimed to investigate the tumor architecture and spatial distribution of tumor immune infiltrate and proliferating tumor cells using digital image analysis. Antibodies against Ki67 (proliferation marker) and CD45 (leukocyte common antigen), and a routine Haematoxylin and Eosin stain were applied to serial sections of 450 full-face tumors via chromogenic immunohistochemistry, as outlined previously [1]. Digital image analysis was performed using open-source software, QuPath [2]. Pixel classifiers were trained and validated against an expert pathologist in order to define observed lymphocytes as tumor or stromal-infiltrating, and to establish a classifier to quantify the tumor-stroma ratio (TSR) and infiltrating tumor area. Distances of CD45-positive cells from tumor were computed, along with autocorrelation statistics [3,4] of CD45 and Ki67 hotspots; firstly in order to quantify spatial heterogeneity, and secondly to examine whether Ki67 as a component gene in the Oncotype Dx assay has a foundation in tumor biology or is being confounded by potentially Ki67-positive lymphocytes. Subdividing by Oncotype Dx risk categories, no significant difference in TSR was observed (p=0.09799), neither for intermediary risk patients receiving hormone therapy alone or in combination with chemotherapy (p=0.3873). While there was an observed trend overall (p=0.092), no significance was found for recurrence between intermediary risk subcategories (HT alone: p=0.393, HT+CT: p=0.288). However, in the cohort as a whole, median TSR was 0.3215 (range 0 - 5.023), with statistically significant differences in recurrence risk observed (cohort high v low by median TSR. HR: 6.356, 95CI: 2.263-17.84, p<0.0001).

Citation Format: Zak Kinsella, Anna Blümel, Mairi Lucas, Andreas Lindner, Claudia A. Gonzalez, Arman Rahman, Joanna Fay, Tony O'Grady, Verena Murphy, John Crown, Cathy Kelly, William Gallagher, Darran O'Connor. Modelling the spatial heterogeneity of CD45-positive tumor infiltrating lymphocytes in early-stage, estrogen receptor-positive breast cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5787.

CD45-positive tumor infiltrating lymphocytes in early-stage hormone-positive, HER2-negative (ER+/HER2-) breast cancer: Correlation with proliferation and prognostic signature scores

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Background: Tumour infiltrating lymphocytes (TILs), have been associated in higher responses to treatment and are thought to be a prognostic marker in a number of cancer types. The role of TILs in breast cancer varies depending on the molecular subtype of the disease. In hormone positive, HER2-negative breast cancer, the significance of TILs is less clear, partly due to the paucity of data in this area. We aim to assess overall TILs in early-stage, hormone-positive, HER2-negative (ER+/HER2-) breast cancer and its relationship with proliferation index, Ki67, and the 21-gene recurrence score. Methods: Archival patient tissue samples of early-stage, ER+/HER2- breast cancer from the Irish arm of the TAILORx clinical trial were used. Full-face sections of these tumours were stained with anti-CD45 antibody (DAKA clone M0701) via the automated Leica Bond III system. A watershed cell-detection algorithm from the open-source digital pathology software, QuPath, was fine-tuned to identify true cell objects and positive immune markers. Optimised detection parameters were used to calculate the percentage of overall CD45+ cells (CD45%) within the tumour area. Patient TIL categories were dichotomised into High v Low CD45%, with 10% chosen as the threshold. CD45% was further correlated with proliferation index, clinical data, and 21-gene recurrence score. Results: 409 samples were included in the analysis. The mean CD45% was 5.96, with samples ranging from 0.13 to 78.86. The majority of samples were in the range of 0-10% of CD45% positivity with 89% (n = 367) patients in this category. Stratification of the cohort by 21-gene-recurrence score (RS) into Low, Intermediate and High, showed a statistically significantly high CD45% in patients with a High RS compared to Low RS (p = 0.0015). When divided by recurrence score group, high CD45% trended toward a lower disease free survival (DFS) when compared to low CD45%, with statistical significance found in those in the Intermediate RS chemotherapy treatment arm (p = 0.009). Conclusions: The role of TILs in ER+/HER2- breast cancer is still undefined. While a High RS was associated with a higher percentage of CD45-positive lymphocytes, the impact on recurrence and response to treatment remains unclear. Further studies to assess the role of different tumour infiltrating lymphocyte phenotypes, and the spatial distribution of assessed markers, are needed.

Assessment of tumour infiltrating subpopulations and pathological complete response using multiplex immunohistochemistry and digital pathology in early HER2+ breast cancer

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Background: The treatment of HER2+ breast cancer (BC) has improved substantially with the use of targeted therapies, and patients achieving pathological complete response (pCR) following neoadjuvant therapy have significantly improved disease free survival. However, there is currently no way to determine which patients are most likely to respond to neoadjuvant HER2-targeting treatment. Growing evidence indicates tumour infiltrating lymphocytes influence HER2+ BC outcome. We hypothesize that a deeper investigation of the immune landscape of HER2+ patient tumours may improve patient stratification and identify an immune profile associated with pCR. Methods: 3plex immunohistochemistry panels identifying immune cell subpopulations and tertiary lymphoid structures were applied to HER2+ BC tumors (pre-treatment N=19, post-treatment N=9) of patients of the neoadjuvant TCHL clinical trial (NCT01485926), who received HER2-targeting therapy. Quantitative analysis of CD3+, CD20+, DC-Lamp+, CD4+, and CD8+ immune cells on multi-labelled whole-slide images of TCHL tumor sections was performed using artificial intelligence image analysis models. Patient-specific densities of each cell type in tumor regions were determined to facilitate assessment of pre-treatment differences in target immune subpopulations in complete, partial, and non-responders. Results: Statistical analysis demonstrated a trend for higher densities of each immune subpopulation in pre-treatment biopsies of pCR vs. non-pCR patients. Patient categorisation based on median threshold demonstrated patients achieving pCR are more frequently high for each immune cell type assessed, while non-pCR patients are more frequently in the low category. Investigation of association of pre-treatment immune infiltrate with clinicopathological features demonstrated trends for higher levels of T-cell infiltration in later stage and hormone receptor negative patients. Conclusions: Multiplex IHC is an optimal technique for the concurrent assessment of multiple target markers in patient tissue, which can be quantitatively analyzed in a high throughput manner using AI models. The findings of this preliminary study support recent evidence regarding the role of tumor infiltrating immune cells in HER2+ BC outcome and warrant further investigation in a larger cohort.

An Insight Into the Driver Mutations and Molecular Mechanisms Underlying Mucinous Adenocarcinoma of the Rectum

BACKGROUND

Mucinous adenocarcinoma of the rectum accounts for 10% of all rectal cancers and has an impaired response to neoadjuvant chemoradiotherapy and worse overall survival. To date, insufficient genomic research has been performed on this histological subtype.

OBJECTIVE

This study aims to define the mismatch repair deficiency rate and the driver mutations underpinning mucinous adenocarcinoma of the rectum and to compare it with rectal adenocarcinoma not otherwise specified.

DESIGN

Immunohistochemistry and sequencing were performed on tumor samples from our tumor biobank.

SETTINGS

This study was conducted across 2 tertiary referral centers.

PATIENTS

Patients with mucinous adenocarcinoma and rectal adenocarcinoma not otherwise specified who underwent rectal resection between 2008 and 2018 were included.

MAIN OUTCOME MEASURES

Mismatch repair status was performed by immunohistochemical staining. Mutations in the panel of oncogenes and tumor suppressor genes were determined by sequencing on the MiSeq V3 platform.

RESULTS

The study included 33 patients with mucinous adenocarcinoma of the rectum and 100 patients with rectal adenocarcinoma not otherwise specified. Those with mucinous adenocarcinoma had a mismatch repair deficiency rate of 12.1% compared to 2.0% in the adenocarcinoma not otherwise specified cohort (p = 0.04). Mucinous adenocarcinoma and adenocarcinoma not otherwise specified rectal tumors had similar mutation frequencies in most oncogenes and tumor suppressor genes. No difference was found in the KRAS mutation rate (50.0% vs 37.1%, p = 0.29) or BRAF mutation rate (6.7% vs 3.1%, p = 0.34) between the cohorts. No difference was found between the cohorts regarding recurrence-free (p = 0.29) or overall survival (p = 0.14).

LIMITATIONS

The major limitations of this study were the use of formalin-fixed, paraffin-embedded tissue over fresh-frozen tissue and the small number of patients included, in particular, in the mucinous rectal cohort.

CONCLUSIONS

Most mucinous rectal tumors develop and progress along the chromosomal instability pathway. Further research in the form of transcriptomics, proteomics, and analysis of the effects of the mucin barrier may yield valuable insights into the mechanisms of resistance to chemoradiotherapy in this cohort. See Video Abstract at http://links.lww.com/DCR/B464.

UNA PERCEPCIN SOBRE MUTACIONES IMPULSORAS Y MECANISMOS MOLECULARES SUBYACENTES AL ADENOCARCINOMA MUCINOSO DEL RECTO

ANTECEDENTES:El adenocarcinoma mucinoso del recto, representa el 10% de todos los cánceres rectales y tiene una respuesta deficiente a la quimioradioterapia neoadyuvante y una peor supervivencia en general. A la fecha, se han realizado muy pocas investigaciones genómicas sobre este subtipo histológico.OBJETIVO:Definir la tasa de deficiencia en la reparación de desajustes y mutaciones impulsoras, que sustentan el adenocarcinoma mucinoso del recto y compararlo con el adenocarcinoma rectal no especificado de otra manera.DISEÑO:Se realizaron inmunohistoquímica y secuenciación en muestras tumorales de nuestro biobanco de tumores.AJUSTE:El estudio se realizó en dos centros de referencia terciarios.PACIENTES:Se incluyeron pacientes con adenocarcinoma mucinoso y adenocarcinoma no especificado de otra manera, sometidos a resección rectal entre 2008 y 2018.PRINCIPALES MEDIDAS DE RESULTADO:El estado de reparación de desajustes se realizó mediante tinción inmunohistoquímica. Las mutaciones en el panel de oncogenes y genes supresores de tumores, se determinaron mediante secuenciación en la plataforma MiSeq V3.RESULTADOS:El estudio incluyó a 33 pacientes con adenocarcinoma mucinoso del recto y 100 pacientes con adenocarcinoma del recto no especificado de otra manera. Aquellos con adenocarcinoma mucinoso, tenían una tasa de deficiencia de reparación de desajustes del 12,1% en comparación con el 2,0% en la cohorte de adenocarcinoma no especificado de otra manera (p = 0,04). El adenocarcinoma mucinoso y el adenocarcinoma no especificado de otra manera, tuvieron frecuencias de mutación similares en la mayoría de los oncogenes y genes supresores de tumores. No se encontraron diferencias en la tasa de mutación de KRAS (50,0% frente a 37,1%, p = 0,29) o la tasa de mutación de BRAF (6,7% frente a 3,1%, p = 0,34) entre las cohortes. No se encontraron diferencias entre las cohortes con respecto a la supervivencia libre de recurrencia (p = 0,29) o la supervivencia global (p = 0,14).LIMITACIONES:Las mayores limitaciones de este estudio, fueron el uso de tejido embebido en parafina y fijado con formalina, sobre el tejido fresco congelado y el pequeño número de pacientes incluidos, particularmente en la cohorte mucinoso rectal.CONCLUSIONES:La mayoría de los tumores rectales mucinosos se desarrollan y progresan a lo largo de la vía de inestabilidad cromosómica. La investigación adicional en forma transcriptómica, proteómica y análisis de los efectos de la barrera de la mucina, puede proporcionar información valiosa sobre los mecanismos de resistencia a la quimioradioterapia, en esta cohorte. Consulte Video Resumen en http://links.lww.com/DCR/B464.

Note: On the deconvolution of Kelvin probe force microscopy data

In Kelvin probe force microscopy (KPFM) proper interpretation of the data is often difficult because the measured surface potential is affected by the interaction of the cantilever with the sample. In this work, the tip's interaction with a modeled surface potential distribution was simulated, leading to a calculated KPFM image. Although simplified, the calculation is capable of showing the influence of the cantilever in the correct qualitative manner, proven by a comparison with experimental data. Additionally, a deconvolution was performed on the simulated image, showing that for simple geometries revealing the "real" surface potential data is possible in principle.

Effects of ethinylestradiol on the renin-angiotensin-aldosterone-system and on plasma transcortin in women and men

The effects of ethinylestradiol (1 mug/kg body weight daily) on plasma renin substrate concentration, other factors of the renin-aldosterone-system, and on the cortisol-binding capacity of transcortin were determined in 8 young men and 9 young women. The absolute and relative elevation of plasma renin substrate after 5, 14, and 24 days of ethinylestradiol administration was significantly (P less than 0.001) greater in females than males. Control and posttreatment transcortin levels were also higher in women than men, but the percentage increase did not differ between males and females. It is likely that sex differences in the response of plasma renin substrate to the estrogen are due to differences in hepatic synthesis and/or release of renin substrate. In females, plasma renin activity, angiotensin II concentration, and urinary aldosterone excretion rose significantly although less markedly than plasma renin substrate concentration, while in males only the increase in plasma angiotensin II concentration was significant. These results indicate that no safe conclusions on metabolic effects of estrogen treatment in women can be drawn from experiments carried out in male subjects.