Table 1.

PTEN-mediated immunogenicity in different types of tumors

Tumor	Main evidence	Experimental setup and methods
Lung cancer [8]	A decrease in PTEN expression contributes to cellular unresponsiveness to IFN-γ	Cell lines PC14PE6/AS2 A549	shRNA, plasmid transfection, WB, FC, luciferase reporter assay, intracellular ROS assay
GBM [22]	Tumors had increased levels of B7-H1 protein and tumor-specific T cells lysed human glioma targets expressing PTENwt more effectively than those expressing PTENmutant	U87MG Cell line and primary cultures	FC, RT-PCR, IHC, WB, NB
Prostate cancer [23]	Cytokines released by PTEN-null senescent prostate tumors drive an immunosuppressive TME, Jak2/Stat3 pathway is activated in PTENpc−/− senescent tumors	Mice models Ptenpc+/+, Ptenpc−/− Ptenpc−/−; Stat3pc−/−	MACS, Cytokine array, FACS, CD8+ suppression assay, pStat3, WB, IHC, IF, GZMB mRNA, H&E
Melanoma [24]	PTEN negatively regulates the expression of immunosuppressive cytokines and PD-L1 by inhibiting the PI3K pathway	Cell lines (PTEN-defective vs. PTEN expressing pairs)	Expression of the IL-10, IL-6, VEGF, PI3K inhibitor treatment
	Melanoma samples lacking brisk host responses showed a higher tendency to lose PTEN	Brisk host response n = 33, without brisk host responses n = 34	IHC (CD3 and PTEN)
Melanoma [25]	PTEN loss causes resistance to T cell mediated response	Cell line A375 PTENsilenced vs control	shRNA, T cell treatment, Casp3 cleavage assay
		Mice tumor model PTENsilenced vs control	Luciferase expressing T cells treatment, bioluminescence imaging, tumor size, survival
	PTEN absent tumor cells have lower CD8+ T cell infiltration	Clinical human samples	135 resected tumors, IHC
		TCGA	Lymphocyte activation score, cytolic activity, expressions of LCK, IFNγ, GZMB
	PTEN loss promotes resistance to immune infiltration of tumors through the production of inhibitory cytokines	Mice xenografts model PTENsilenced vs control	Chemokines and cytokines by Luminex assay
		Clinical human samples	IHC confirmed increased VEGF in regions with PTEN loss
Sarcoma [26]	PTEN loss is associated with induction of an immunosuppressive microenvironment and resistance to PD-1 blockade	Primary tumor, treatment-resistant metastatic tumor and germline tissue from a clinical case	IHC, RNA-seq and WES
	Tumors with biallelic PTEN loss had significantly lower levels of mRNA expression of PDCD1, CD8A, IFNG, PRF1, and GZMA compared to PTENwt tumors	TCGA	Mutation, copy number, RNA-seq data from 241 untreated primary sarcomas
Prostate cancer [27]	PTEN loss leads to upregulated inflammatory and cytokine–cytokine receptor signaling.	PTEN null murine models Cell lines	FACS, IHC, Q-RT-PCR, T cell suppression assay, laser capture and microarray
	Pro-inflammatory cytokines produced by PTEN null prostate are the major causes of MDSC expansion
Lymphoma [11]	Low PTEN mRNA expression is associated with down-regulation of a group of genes involved in immune responses and B-cell development/differentiation and poorer survival	478 cases (training cohort) 269 cases (validation cohort)	IHC, FISH, Gene sequencing and expression array
GBM [28]	PTEN mutations associated with immuno suppressive expression signatures in ICIs non-responders	66 patients treated with PD-1 inhibitors profiled across a variety of timepoints, collecting DNA, RNA, tissue imaging	WES, qmIF, lymphocyte clonality analysis, RNA seq
Prostate cancer [29]	FoxP3+ Tregs were significantly increased in PTEN deficient PCa, PTEN deficiency is linked to an immunosuppressive state in PCa with distinct changes in the frequency of immune cell types in tumors from different metastatic sites	741 primary and 96 metastatic tumors, 94 radical prostatectomy specimens for IH validation	in silico analysis and IH validation for IDO1 and PDL1

FACS fluorescence activated cell sorting, FC flow cytometry, FISH fluorescein in situ hybridization, GBM glioblastoma, GZMB granzyme B, H&E hematoxylin and eosin, IF immunofluorescence, IHC immunohistochemistry, IL Interleukin, LCK lymphocyte cell-specific protein-tyrosine kinase, MACS magnetic-activated cell sorting, MDSC myeloid-derived suppressor cell, MHC major histocompatibility complex, NB Northern blot, PI3K phosphoinositide 3-kinase, qmIF quantitative multiplex immunofluorescence analysis, RT-PCR reverse transcription-polymerase chain reaction, ROS reactive oxygen species, shRNA short hairpin RNA, TCGA the cancer genome atlas, TME tumor microenvironment, VEGF vascular endothelial growth factor, WB Western blot, WES whole exome sequencing