Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Jun 3;24(1):38.
doi: 10.1186/s13058-022-01532-0.

Hypoxia-regulated carbonic anhydrase IX (CAIX) protein is an independent prognostic indicator in triple negative breast cancer

Chong Hui Clara Ong  1 , Dong Yeul Lee  1   2 , Bernett Lee  3 , Huihua Li  4   5 , Jeffrey Chun Tatt Lim  6 , Johnathan Xiande Lim  1 , Joe Poh Sheng Yeong  1   6 , Hiu Yeung Lau  1 , Aye Aye Thike  1   7 , Puay Hoon Tan  1   7 , Jabed Iqbal  8   9
Affiliations

Hypoxia-regulated carbonic anhydrase IX (CAIX) protein is an independent prognostic indicator in triple negative breast cancer

Chong Hui Clara Ong et al. Breast Cancer Res. .

Abstract

Background: The effect of extracellular microenvironment (hypoxia and pH) has been regarded as a key hallmark in cancer progression. The study aims to investigate the effects of carbonic anhydrase IX (CAIX), a key hypoxia-inducible marker, in triple-negative breast cancer (TNBC) in correlation with clinicopathological parameters and predicting survival outcomes.

Methods: A total of 323 TNBC cases diagnosed at the Department of Anatomical Pathology, Singapore General Hospital from 2003 to 2013 were used. Immunohistochemical staining (IHC) was performed using CAIX antibody and digital mRNA quantification was performed using NanoString assays. CAIX membranous expression was correlated with clinicopathological parameters using Chi-squared test or Fisher's exact tests. Disease-free survival (DFS) and overall-survival (OS) were estimated using Kaplan-Meier analysis and compared between groups with the log-rank test.

Results: Forty percent of TNBCs were observed to express CAIX protein and demonstrated significant association with larger tumour size (P = 0.002), higher histological grade (P < 0.001), and significantly worse disease-free survival (DFS) and overall survival (OS) (after adjustment: HR = 2.99, 95% CI = 1.78-5.02, P < 0.001 and HR = 2.56, 95% CI = 1.41-4.65, P = 0.002, respectively). Gene ontology enrichment analysis revealed six significantly enriched cellular functions (secretion, cellular component disassembly, regulation of protein complex assembly, glycolytic process, cellular macromolecular complex assembly, positive regulation of cellular component biogenesis) associated with genes differentially expressed (CAIX, SETX, WAS, HK2, DDIT4, TUBA4α, ARL1). Three genes (WAS, SETX and DDIT4) were related to DNA repair, indicating that DNA stability may be influenced by hypoxia in TNBC.

Conclusions: Our results demonstrate that CAIX appears to be a significant hypoxia-inducible molecular marker and increased CAIX protein levels are independently associated with poor survival in TNBC. Identification of CAIX-linked seven gene-signature and its relationship with enriched cellular functions further support the implication and influence of hypoxia-mediated CAIX expression in TNBC tumour microenvironment.

Keywords: CAIX; Carbonic anhydrase IX; Hypoxia; Hypoxia gene panel; Prognosis; TNBC; Triple-negative breast cancer.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be constructed as a potential conflict of interest. Prof Tan Puay Hoon declares non-financial competing interest as she is on the Breast Cancer Research Journal editorial board.

Figures

Fig. 1
Fig. 1
Representative immunohistochemical staining of A negative and B positive CAIX tumour cell expression in TNBC sections
Fig. 2
Fig. 2
Kaplan–Meier analysis of A DFS and B OS outcomes in patients with positive CAIX expression
Fig. 3
Fig. 3
CAIX Strip-plot analysis to mRNA expression of A CAIX, B DDIT4, C TUBA4α, D HK2, E ARL1, F WAS, and G SETX
Fig. 4
Fig. 4
Expression level of a panel of seven significantly DEGs in triple-negative breast cancer (TNBC) patients
See this image and copyright information in PMC

References

    1. Lehmann BD, Bauer JA, Chen X, Sanders ME, Chakravarthy AB, Shyr Y, et al. Identification of human triple-negative breast cancer subtypes and preclinical models for selection of targeted therapies. J Clin Invest. 2011;121(7):2750–2767. doi: 10.1172/JCI45014. - DOI - PMC - PubMed
    1. Yin L, Duan JJ, Bian XW, Yu SC. Triple-negative breast cancer molecular subtyping and treatment progress. Breast Cancer Res. 2020;22(1):61. doi: 10.1186/s13058-020-01296-5. - DOI - PMC - PubMed
    1. Jing X, Yang F, Shao C, Wei K, Xie M, Shen H, et al. Role of hypoxia in cancer therapy by regulating the tumor microenvironment. Mol Cancer. 2019;18(1):157. doi: 10.1186/s12943-019-1089-9. - DOI - PMC - PubMed
    1. Muz B, de la Puente P, Azab F, Azab AK. The role of hypoxia in cancer progression, angiogenesis, metastasis, and resistance to therapy. Hypoxia (Auckl) 2015;3:83–92. doi: 10.2147/HP.S93413. - DOI - PMC - PubMed
    1. Pastorekova S, Ratcliffe PJ, Pastorek J. Molecular mechanisms of carbonic anhydrase IX-mediated pH regulation under hypoxia. BJU Int. 2008;101(Suppl 4):8–15. doi: 10.1111/j.1464-410X.2008.07642.x. - DOI - PubMed

Publication types