PCSK1 Overexpression in Rectal Cancer Correlates with Poor Response to Preoperative Chemoradiotherapy and Prognosis

Figures & data

Table 1 Summary of Differentially Expressed Genes Associated with Cell–Cell Signaling (GO: 0007267) in Relation to Response to CCRT in Rectal Carcinoma

Probe	Comparison Log Ratio	Comparison p-value	Gene Symbol	Gene Name	Biological Process	Molecular Function
205767_at	−1.339	0.0001	EREG	Epiregulin	Anatomical structure morphogenesis, angiogenesis, cell differentiation, cell proliferation, cell–cell signaling, cytokine and chemokine-mediated signaling pathway, epidermal growth factor receptor signaling pathway, female meiosis, keratinocyte differentiation, keratinocyte proliferation, luteinizing hormone signaling pathway, mRNA transcription, multicellular organismal development, negative regulation of cell proliferation, negative regulation of epithelial cell proliferation, negative regulation of smooth muscle cell differentiation, negative regulation of transcription, oocyte maturation, organ morphogenesis, ovarian cumulus expansion, ovulation, positive regulation of DNA replication, positive regulation of cell proliferation, positive regulation of cytokine biosynthetic process, positive regulation of cytokine production, positive regulation of epidermal growth factor receptor activity, positive regulation of fibroblast proliferation, positive regulation of innate immune response, positive regulation of interleukin-6 biosynthetic process, positive regulation of mitosis, positive regulation of phosphorylation, positive regulation of protein kinase activity, positive regulation of smooth muscle cell proliferation, primary follicle stage; oogenesis, regulation of progression through cell cycle, wound healing	Epidermal growth factor receptor binding, growth factor activity, protein binding, protein heterodimerization activity
205825_at	1.8447	<0.0001	PCSK1	Proprotein convertase subtilisin/kexin type 1	Cell–cell signaling, metabolic process, proteolysis	Calcium ion binding, hydrolase activity, peptidase activity, proprotein convertase 1 activity, serine-type endopeptidase activity, subtilase activity
210163_at	−1.2994	<0.0001	CXCL11	Chemokine (C-X-C motif) ligand 11	Cell–cell signaling, chemotaxis, immune response, inflammatory response, signal transduction	Chemokine activity, cytokine activity
210861_s_at	1.1635	<0.0001	WISP3	WNT1-inducible-signaling pathway protein 3	Cell–cell signaling, regulation of cell growth, signal transduction	Growth factor activity, insulin-like growth factor binding
211122_s_at	−1.3734	0.0001	CXCL11	Chemokine (C-X-C motif) ligand 11	Cell–cell signaling, chemotaxis, immune response, inflammatory response, signal transduction	Chemokine activity, cytokine activity

Figure 1 Analysis of gene expression in CCRT responders versus non-responders from a published transcriptomic dataset of rectal cancers (GSE35452). Clustering analysis of genes related to cell-cell signaling indicated PCSK1 is the most significantly upregulated gene in patients responsive to CCRT. Tissue specimens from responders (yellow lines) and non-responders (blue lines) are indicated on top of the heatmap, and expression levels of upregulated and downregulated genes are expressed as a spectrum of brightness of red and green, respectively, with those unaltered in mRNA.

Table 2 Associations and Comparisons Between PCSK1 Expression and Clinicopathological Factors in 172 Rectal Cancer Patients Receiving Preoperative CCRT

Parameters		No.	PCSK1 Expression		p-value
			Low Exp	High Exp
Gender	Male	108	49	59	0.115
	Female	64	37	27
Age (Years)	<70	106	50	56	0.347
	≧70	66	36	30
Pre-Tx Tumor Status (Pre-T)	T1–T2	81	49	32	0.009*
	T3–T4	91	37	54
Pre-Tx Nodal Status (Pre-N)	N0	125	73	52	<0.001*
	N1–N2	47	13	34
Post-Tx Tumor Status (Post-T)	T1–T2	86	60	26	<0.001*
	T3–T4	86	26	60
Post-Tx Nodal Status (Post-N)	N0	123	74	49	<0.001*
	N1–N2	49	12	37
Vascular Invasion	Absent	157	84	73	0.003*
	Present	15	2	13
Perineurial Invasion	Absent	167	86	81	0.023*
	Present	5	0	5
Tumor Regression Grade	Grade 0–1	37	10	27	<0.001*
	Grade 2–3	118	62	56
	Grade 4	17	14	3

Note: *Statistically significant.

Figure 2 Immunohistochemical staining for proprotein convertase subtilisin/kexin-type 1 (PCSK1) in rectal cancers. The non-neoplastic colonic mucosa (A) reveals no expression of PCSK1 as compared with rectal cancers with low expression (B) and high expression (C) of PCSK1 in pretreatment specimens, respectively.

Table 3 Univariate Log-Rank Analysis for Important Clinicopathological Variables and PCSK1 Expression

Parameters		No. of Cases	DSS		LRFS		MeFS
			No. of Events	p-value	No. of Events	p-value	No. of Events	p-value
Gender	Male	108	20	0.9026	7	0.2250	17	0.3520
	Female	64	11		20		14
Age (Years)	<70	106	19	0.8540	18	0.6615	20	0.7427
	≧70	66	12		9		11
Pre-Tx Tumor Status (Pre-T)	T1–T2	81	10	0.0776	10	0.2261	11	0.1745
	T3–T4	91	21		17		20
Pre-Tx Nodal Status (Pre-N)	N0	125	19	0.0711	15	0.0070*	19	0.0973
	N1–N2	47	21		12		12
Post-Tx tumor status (Post-T)	T1–T2	86	7	0.0006*	7	0.0040*	8	0.0033*
	T3–T4	86	24		20		23
Post-Tx Nodal Status (Post-N)	N0	123	21	0.5998	16	0.1320	20	0.4634
	N1–N2	49	10		11		11
Vascular Invasion	Absent	157	25	0.0184*	21	0.0028*	27	0.4470
	Present	15	6		6		4
Perineurial Invasion	Absent	167	29	0.2559	25	0.0940	30	0.9083
	Present	5	2		2		1
Tumor Regression Grade	Grade 0–1	37	13	0.0038*	10	0.0090*	14	0.0006*
	Grade 2–3	118	17		17		16
	Grade 4	17	1		0		1
Down Stage fter CCRT	Non-Sig.	150	29	0.1651	24	0.5961	30	0.0853
	Sig. (≥2)	22	2		3		1
PCSK1 Expression	Low Exp.	86	4	<0.0001*	8	0.0063*	7	0.0008*
	High Exp.	86	27		19		24

Note: *Statistically significant.

Abbreviations: DSS, disease-specific survival; LRFS, local recurrence-free survival; MeFS, metastasis-free survival.

Table 4 Multivariate Survival Analysis

Parameters	DSS			LRFS			MeFS
	HR	95% CI	p-value	HR	95% CI	p-value	HR	95% CI	p-value
Tumor Regression Grade	1.838	0.914–3.690	0.088	2.433	1.120–5.291	0.025*	2.242	1.114–4.525	0.024*
PCSK1 Expression	5.478	1.789–16.774	0.003*	1.299	0.634–4.276	0.594	2.395	0.965–5.945	0.060
Vascular Invasion	1.861	0.737–4.694	0.189	2.427	0.877–6.716	0.088	–	–	–
Post-Tx Tumor Status (Post-T)	1.689	0.693–4.117	0.249	1.924	0.758–4.880	0.168	1.677	0.699–4.024	0.247
Pre-Tx Nodal Status (Pre-N)	–	–	–	1.905	0.793–4.576	0.150	–	–	–

Note: *Statistically significant.

Abbreviations: DSS, disease-specific survival; LRFS, local recurrence-free survival; MeFS, metastasis-free survival; HR, hazard ratio; CI, confidence interval.

Figure 3 Kaplan–Meier survival curves plotted to predict survival. Using the Log rank test, rectal cancer patients with high expression of PCSK1 had an inferior disease-specific survival (A), local recurrence-free survival (B) and metastasis-free survival (C).