L1 is a potential marker for poorly-differentiated pancreatic neuroendocrine carcinoma

Table 1 Characteristics of the patients and levels of L1 expression n(%)

Variable	Patients	L1-positive tumors
Total	63	5 (7.9)
Male	32(50.8)	4 (12.5)
Female	31(49.2)	1 (3.2)
WHO classification of neuroendocrine pancreatic tumour
Well-differentiated neuroendocrine tumour (grade 1a)	50(79.4)	1 (2.0)
Well-differentiated neuroendocrine carcinoma (grade 1b)	4(6.3)	0
Poorly-differentiated neuroendocrine carcinoma (grade 2)	9(14.3)	4 (44.4)
Hormone production
Yes	11(17.5)	0
No	52(82.5)	5 (9.6)
Multiple endocrine neoplasia (MEN)-I
MEN-I	6(9.5)	0
No MEN-I	57(90.5)	5 (8.8)

Table 2 Correlation of L1 expression with WHO classification

WHO classification	L1-negative	L1-positive	Total
Well-differentiated neuroendocrine tumors and Well-differentiated neuroendocrine carcinomas (grade 1a and 1b)	53	1	54
Poorly-differentiated neuroendocrine carcinomas (grade 2)	5	4	9
Total	58	5	63

P<0.01 by Fisher's test (two-sided)