p21 and p27 immunoexpression in gastric well differentiated endocrine tumors (ECL-cell carcinoids)

Table 1 Gastric endocrine tumor classification, WHO[6]

Classification	Diameter	Ki-67 PI1	Mitosis	Extension
Well differentiated endocrine tumor (carcinoid tumor)	≤ 1 cm	≤ 2%	≤ 2/10 HPF2	Mucosa- submucosa
Well differentiated endocrine carcinoma (malignant carcinoid)	> 1 cm	> 2%	> 2/10 HPF2	Muscularis propria and beyond
Poorly differentiated endocrine carcinoma (small cell carcinoma)	Any diameter	> 15%	> 10/10 HPF2	Vascular and neural invasion

¹Proliferation index;

²High power field.

Table 2 Accompanying histopathologic features

Pathology	Patients (n)	Rate (%)
Atrophy	8	50.0
Neuroendocrine hyperplasia	7	43.8
Intestinal metaplasia	9	56.3
Neuroendocrine dysplasia	3	18.8
Multifocality	5	31.4
Submucosal extension	8	50.0

Table 3 p21, p27, Ki-67 staining ratios (%)

Gene	Mean ± SD	Range
p21	1.09 ± 1.44	0-4
p27	43.58 ± 31.27	10-95
Ki-67	0.7 ± 0.94	0-3

Table 4 p21 and p27 expressions and clinicopathologic features (%)

Clinicopathologicfeature		p21	P3	p27	P3
Gender	Male	1.5	0.60	58.0	0.34
	Female	0.85		36.4
Localization	Fundus	3.0	< 0.05	90.5	< 0.05
	Other	0.7		34.2
Multifocality	Multifocal	0.7	0.57	45.7	0.92
	Single focus	1.25		42.9
NEH1	Present	1.0	0.842	50.8	0.64
	Absent	1.16		37.5
NED1	Present	0.7	0.57	45.7	0.80
	Absent	1.25		42.8
Atrophy	Atrophic	1.3	0.47	46.4	0.50
	Non-atrophic	0.8		32.5
Intestinal metaplasia	IM2 (+)	χ4	χ4	49.6	0.09
	IM2 (-)	X4		16.5
Submucosal extension	Present	1.0	0.893	49.3	0.67
	Absent	0.8		30.5
p27 immunoexpression	p21 expressing	χ4	χ4	68.0	< 0.05
	p21 (-)	χ4		21.8
Follow-up	Recurrent	0.0	0.094	26.7	0.51
	Non-recurrent	1.5		49.9

¹Neuroendocrine cell hyperplasia-diysplasia;

²Intestinal metaplasia;

³Mann-Whitney U test;

⁴Result is omitted since p21 value was constant in IM (-) cases.