High expression of Sam68 in sacral chordomas is associated with worse clinical outcomes

Figures & data

Figure 1 Representative expression of Sam68 and Ki-67 and their correlation in sacral chordomas.

Notes: (A) Low expression of Sam68; (B) low expression of Ki-67; (C) high expression of Sam68; (D) high expression of Ki-67; (E) negative control. All magnification, ×400. (F) Positive correlation between Sam68 expression and Ki-67 index in sacral chordomas using Spearman’s rank correlation test.

Table 1 Expression of Sam68 in sacral chordomas compared with distant normal tissues

Tissue samples	Total	Sam68 expression		P-value
		High (%)	Low (%)
Sacral chordomas	40	24 (60)	16 (40)	0.001
Distant normal tissues	20	3 (15)	17 (85)

Table 2 Association between Sam68 expression and the clinicopathologic characteristics of patients with sacral chordoma

Variables	Total	Sam68 expression		P-value
		High	Low
Age (years)				0.505
<50	15	10	5
≥50	25	14	11
Gender				0.601
Male	23	13	10
Female	17	11	6
Tumor location				0.292
Above S3	24	16	8
S3 and below	16	8	8
Tumor size (cm)				0.343
<5	14	7	7
≥5	26	17	9
Tumor grade				0.581
High	27	17	10
Low	13	7	6
Tumor stage				0.129*
IA	9	3	6
IB	4	4	0
IIA	4	2	2
IIB	20	12	8
III	3	3	0
Surrounding muscle invasion				<0.001
Yes	25	21	4
No	15	3	12
Type of resection				0.006
EI	18	15	3
EA	22	9	13
Ki-67 index				<0.001
High	24	21	3
Low	16	3	13

Note:

* Using the Fisher’s exact test.

Abbreviations: EA, Enneking appropriate; EI, Enneking inappropriate.

Figure 2 Kaplan–Meier curves of the local recurrence-free survival of patients with sacral chordoma.

Notes: (A) Stratified by Sam68 expression; (B) stratified by Ki-67 index; (C) stratified by Sam68/Ki-67 coexpression (low/low and others); (D) stratified by Sam68/Ki-67 coexpression (high/high and others); (E) stratified by tumor stage; (F) stratified by surrounding muscle invasion; (G) stratified by the type of tumor resection.
Abbreviations: EA, Enneking appropriate; EI, Enneking inappropriate.

Figure 3 Kaplan–Meier curves of the overall survival of patients with sacral chordoma.

Notes: (A) Stratified by tumor stage; (B) stratified by surrounding muscle invasion; (C) stratified by the type of tumor resection.
Abbreviations: EA, Enneking appropriate; EI, Enneking inappropriate.

Table 3 Kaplan–Meier analysis and multivariate Cox’s proportional hazard analysis of the prognostic factors for the local recurrence-free survival of patients with sacral chordoma

Variables	Categories	Kaplan–Meier analysis	Multivariate analysis
		P-value	P-value	HR (95% CI)
Age (years)	<50/≥50	0.671
Gender	Male/female	0.587
Tumor location	Above S3/S3 and below	0.091
Tumor size (cm)	<5/≥5	0.124
Tumor grade	High/low	0.595
Tumor stage	IA/IB/IIA/IIB/III	<0.001	0.001	2.272 (1.384–3.729)
Surrounding muscle invasion	Yes/no	<0.001	0.001	13.128 (2.793–61.698)
Type of resection	EI/EA	<0.001	0.002	6.678 (2.052–21.736)
Ki-67 index	High/low	0.016	0.552	0.658 (0.166–2.613)
Sam68 expression	High/low	<0.001	0.039	5.929 (1.092–32.188)
Sam68/Ki-67 coexpression	Low/low	<0.001*
	High/high	0.002*
	High/low and low/high

Note:

* Not included in the multivariate analysis because the variables depend on the expression of Sam68 and Ki-67.

Abbreviations: EA, Enneking appropriate; EI, Enneking inappropriate; HR, hazard ratio.

Table 4 Kaplan–Meier analysis and multivariate Cox’s proportional hazard analysis of the prognostic factors for the overall survival of patients with sacral chordoma

Variables	Categories	Kaplan–Meier analysis	Multivariate analysis
		P-value	P-value	HR (95% CI)
Age (years)	<50/≥50	0.362
Gender	Male/female	0.319
Tumor location	Above S3/S3 and below	0.075
Tumor size (cm)	<5/≥5	0.065
Tumor grade	High/low	0.468
Tumor stage	IA/IB/IIA/IIB/III	<0.001	0.049	1.677 (1.002–2.806)
Surrounding muscle invasion	Yes/no	0.032	0.089	6.272 (0.755–52.075)
Type of resection	EI/EA	0.015	0.175	2.254 (0.697–7.291)
Ki-67 index	High/low	0.628
Sam68 expression	High/low	0.228
Sam68/Ki-67 coexpression	Low/low	0.250
	High/high	0.547
	High/low and low/high

Abbreviations: EA, Enneking appropriate; EI, Enneking inappropriate; HR, hazard ratio.