Frequency of HER2/neu overexpression in adenocarcinoma of the gastrointestinal system

Table 1 Positive intensity of HER2/neu staining with respect to study group age

Intensity of HER2/neu staining	Study groups
	Group A	Group B	Group C	Total
No stain or membrane staining < 10% (0)	1	8	8	17
Weak staining ≥ 10% (1+)	2	0	6	8
Moderate staining ≥ 10% (2 +)	6	0	7	13
Strong staining ≥ 10% (3 +)	2	0	10	12
Total	11	8	31	50
Mean age (yr)	52.81 ± 9.41	50.25 ± 9.41	46.51 ± 15.92	48.50 ± 13.62
Minimum age (yr)	40.00	45.00	17.00	17.00
Maximum age (yr)	70.00	60.00	75.00	75.00

χ² = 19.49, P value = 0.000 (regarding ratio of positivity among different groups); χ² = 23.023, P = 0.001 (regarding intensity of positivity among different groups). Group A: Gastric; Group B: Small intestine; Group C: Colorectal; Score 0: Negative HER2/neu protein overexpression; Score 1+, 2+, and 3+: Positive HER2/neu protein overexpression.