Abstract 310: Immunophenotyping tumors by novel multiplex immunofluorescence and AQUA (Automated Quantitative Analyses) algorithms to guide development of immunotherapies

Purpose: Deeper understanding of immune landscape of the tumor microenvironment is critical for exploring and development of next generation immunotherapies. Multiplex fluorescence immunohistochemistry (mFIHC) combined with hypothesis driven spatial profiling algorithms (e.g., AQUA Technology) was found to provide the most powerful predictors of immunotherapies in a systematic meta-analyses of over 8000 patients treated with PD1/L1 pathway blockers (Lu et al., JAMA Oncol 2019).

Study Design: To guide clinical development of next generation and/or combination immunotherapies, we built four novel mFIHC assays to simultaneously explore presence of major immune cell lineages, their spatial relationships and functional attributes. The first assay incorporates antibodies to identify major immune cells lineages (e.g., T-, B-, NK-/T- and subtypes of myeloid cells), the second assay is designed to understand T-cell proliferation (via co-expression of Ki67) or suppression (via co-expression of FoxP3), the third method is focused on quantifying the expression of immune checkpoint inhibitors (e.g., LAG3, PD1 and PD-L1), while, the final assay is designed to explore the IFNγ mediated adaptive resistance and immunosuppression (via co-expression of HLA-DR and IDO1). We will describe the successful development of these clinical grade mFIHC assays that utilize automated staining (Leica Bond RX), imaging (Vectra Polaris) and analyses (AQUA® Technology) workflows on tissue microarrays (TMAs) representing multiple regions of interest including tumor, tumor margin, tumor-associated fibrosis, various adjacent normal tissues, lymphoid structures and/or associated inflammation, and metastatic lesions collected from 100 colorectal, and pancreatic cancer patients.

Results: Sensitivity, accuracy and specificity were confirmed for all mFIHC assays on known positive and negative controls. Excellent reproducibility (less than 35% CV) and precision were observed across instruments, operators and independent experiments for all markers. TMA work is underway and the latest results will be presented.

Conclusion: The validated mFIHC assays helped classify unique immune phenotypes and their interactions. These assays, combined with comprehensive selection of tissues from the tumor microenvironment across multiple cancer subtypes, are expected to enable clinical development of next generation cancer therapies.

Citation Format: Ju Young Kim, John Hoerter, Nathan Roscoe, John Fathman, James Santos, Lori Iaconis, Justin Santos, Minhua Qiu, Jacob Levy, Valerie Tolley, Emmanuel Pacia, Tom Carolan, Xun Li, Patrizia Barzaghi-Rinaudo, Brian Schwartz, Robbin Newlin, Karyn Colman, Andy Schumacher, Deborah Knee, Steven Bender, Margaret McLaughlin, Alexander Savchenko, Thai Tran, Shabnam Tangri, Naveen Dakappagari, Jennifer Bordeaux. Immunophenotyping tumors by novel multiplex immunofluorescence and AQUA (Automated Quantitative Analyses) algorithms to guide development of immunotherapies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 310.

Oviduct-specific glycoprotein is a molecular marker for invasion in endometrial tumorigenesis identified using a relevant mouse model

The light microscopic distinction between complex atypical hyperplasia (CAH) and invasive endometrioid carcinoma (UEC) on endometrial sampling is problematic and often has significant clinical implications. Using mouse models of endometrial tumorigenesis based on two of the most common molecular alterations found in primary human UEC we sought to characterize the transition from CAH to carcinoma to identify clinically useful biomarkers. We used the previously described Pten(+/-); Mlh1(-/-) mouse model. DNA was isolated from microdissected lesions (CAH and carcinoma) and analyzed for LOH and mutations of Pten and additional candidate genes. To identify novel candidate genes associated with invasion, global gene expression profiles were compared from uteri with extensive CAH and carcinoma. The majority of CAHs and carcinomas, arising in this model showed biallelic inactivation of Pten mediated through LOH or intragenic mutation of the wild-type allele suggesting that complete loss of Pten is insufficient for the development of carcinoma. The global gene expression studies detected increased expression of oviduct-specific glycoprotein (OGP) in carcinoma as compared with CAHs. This finding was validated using immunohistochemical staining in a collection of primary human UECs and CAHs. Our studies identify a molecular marker for invasive endometrial cancer that may have clinical significance, and highlight the usefulness of this mouse model in not only understanding the genetic underpinnings of endometrial carcinoma, but as a tool to develop clinically relevant biomarkers.

p16 and Ki-67 immunostaining in atypical immature squamous metaplasia of the uterine cervix: correlation with human papillomavirus detection

CONTEXT

Atypical immature squamous metaplasia (AIM) of the cervix is a loosely defined entity characterized by immature metaplastic cells with mild cytologic atypia.

OBJECTIVE

To examine whether a combination of immunostaining for p16 and Ki-67 could be used to stratify AIM cases into 3 categories: benign, cases with nondiagnostic atypia, and high-grade squamous intraepithelial lesion (HSIL).

DESIGN

The study consisted of 37 cases of AIM, 23 cases of benign cervical mucosa (NEG), and 36 cases of HSIL. All cases were tested for high-risk human papillomaviruses using SPF 10 polymerase chain reaction and immunostained for p16 and Ki-67.

RESULTS

All cases of HSIL were positive for both p16 and Ki-67. All but 2 benign control cases were negative for both p16 and Ki-67. Seven cases of AIM (19%) displayed a pattern of immunostaining identical to HSIL, and these most likely represent a spectrum of HSIL. A total of 54% of cases of AIM were negative for both p16 and Ki-67, consistent with benign reactive atypia. Two AIM cases (5%) were negative for p16 and positive for Ki-67 in the area adjacent to an ulcer, representing regeneration. Finally, 22% of AIM cases were positive for p16 and negative for Ki-67; such cases may represent a precursor of HSIL or, alternatively, a regressing HSIL.

CONCLUSION

The combination of immunostaining for p16 and Ki-67 is helpful in limiting of the number of cases with nondiagnostic atypia of the cervix.