Page 11 - BladderCancerAbstracts

Posters

the rationale for larger studies focusing on predictive and prognostic Investigating sex differences in CD79a+ tumor-infiltrating B
profiles of ER. cells, tertiary lymphoid structures, and response to BCG in
Methods: Nine mUC patients with ER (defined as clinical complete or patients with non-muscle-invasive bladder cancer
partial response to systemic chemotherapy lasting ≥18 months) were Benjamin Ravenscroft , Stephen Chenard , Chelsea Jackson ,
1,2
1
1,2
identified in British Columbia. We performed whole-transcriptome and Priyanka Yolmo , Sadaf Rahimi , Ava Slotman , Katherine Lindale ,
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1,2
1,2
1
targeted-DNA sequencing, and multicolor immunohistochemistry (mIHC) Lina Chen , Tamara Jamaspishvilli 1,2 , Kathrin Tyryshkin 1,2 ,
2
on all available specimens (N=18). For all patients, we included tumor David M. Berman , D. Robert Siemens , Madhuri Koti 1
1,2
1,4
tissues immediately preceding the metastatic event. For 6/9 patients we 1 Queen’s Cancer Research Institute, Kingston, ON, Canada; Department
2
included historic (non-metastatic) serial surgical specimens. For com- of Pathology and Molecular Sciences, Queen’s University, Kingston, ON,
parison, we analyzed two published studies comprising a chemo-naive Canada; Department of Urology, Queen’s University, Kingston, ON,
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muscle-invasive bladder cancer (MIBC) cohort (MIBC-TCGA2017) and Canada
a non-ER mUC cohort (nonER-mUC). Introduction: Despite a higher incidence in males, female patients with
Results: Targeted sequencing showed mutations or copy number altera- NMIBC generally present with advanced disease and display earlier recur-
tions in 27/60 genes across the ER-mUC cohort. Similar to the MIBC- rence and progression post-treatment compared to males. Recurrence
TCGA2017 and the nonER-mUC cohorts, the most commonly mutated post-treatment with intravesical bacillus Calmette-Guérin (BCG) occurs
genes were TP53, KDM6A, KMT2D, and ARID1A. Mutations or deletions in over 50% of patients. Our previous study showed that higher density
in TP53 were enriched in the ER-mUC compared to the MIBC-TCGA2017 of intra-tumoral CD163+ macrophages and B cells is present in patients
and nonER-mUC cohorts (80%, 48%, and 60%, respectively). Mutations with shorter recurrence-free survival (RFS). Given the established sex dif-
in DNA damage repair (DDR) genes were more frequent in ER-mUC ferences in B cell-associated mucosal immune physiology, in this study,
patients compared to MIBC-TCGA2017 and nonER-mUC patient cohorts we evaluated the patterns of B cell infiltration and tertiary lymphoid
(50%, 28%, and 26%, respectively), with ERCC2 being the most com- structure (TLS) formation in pre-treatment tumors from female and male
monly mutated among those. Most (75%) ER-mUC tumors were classed patients with NMIBC.
as luminal by RNA analysis. In contrast, 47% and 44% of patients of the Methods: Spatial immunophenotyping of pre-treatment tumors from
MIBC-TCGA2017 and nonER-mUC cohort, respectively, were luminal. 173 patients (n=34 females and 139 males) treated with BCG at the
mIHC revealed ER-mUC tumors had increased CD8+GzmB+/FoxP3+ cell Kingston Health Sciences Centre, was performed using multiplex immu-
populations compared to a cohort of MIBC patients treated with neoad- nofluorescence assay. The density and spatial distribution of CD79a+ B
juvant chemotherapy (NAC). cells, CD103+ tissue resident memory T cells, Ki67+CD8+ cytotoxic T
Conclusions: Our results suggest that therapeutic success in the con- cells, CD163+ M2 macrophages, including the checkpoints PD-1 and
text of these rare ERs may be multifactorial and conferred by aggressive PD-L1, was determined via automated evaluation and manual validation.
tumor profiles, with multiple molecular mechanisms, including DDR gene Hematoxylin and eosin-stained whole sections from a subset of immu-
alterations, specific transcriptomic subtype, and immune microenviron- nophenotyped tumors were evaluated for the presence and organization
ment. Contrary to previous work in the context of NAC, luminal tumors of TLSs. Immune cell abundance was analyzed using R version 4.1.2.
are enriched among the ER-mUC cohort. This work highlights the need Survival and multivariate analyses were performed using survminer, sur-
for multi-omic platform analyses of a larger number of ER-mUC cases. vival, and finalfit packages. Differences in immune cell density between
response groups were tested using the Mann-Whitney U test. Differences
in survival were time-to-event analyses were performed using Kaplan-
Meier and Cox proportional hazards analyses.
Results: In this cohort, female patients treated with BCG exhibited worse
RFS and progression free survival (PFS) compared to their male coun-
terparts. Tumors from BCG-refractory patients exhibited higher density
of both stromal B cells and M2 like macrophages compared to BCG
responders. Notably, high stromal CD79a+ B cell density was significantly
associated with higher tumor stage and shorter PFS in a multivariable
Cox proportional hazards model that considers gender, age, AUA risk
score, and BCG treatment. High densities of CD8+ cytotoxic T cells, as
well as CD103+ tissue resident memory T cells in either compartment
associated with poor RFS.
Conclusions: Overall, this study suggests a potential role of B cells in
mediating poor response to BCG immunotherapy with a more pro-
nounced influence on female patients compared to males with NMIBC.

CUAJ • MARCH 2023 • VOLUME 17, ISSUE 3(SUPPL1) S9