Table 2.

A) Immunohistochemical sst2A staining levels in relation with undetectable or low levels (< 3’500 dpm/mg) and high levels (≥ 3’500 dpm/mg) of 125I-[Tyr3]-octreotide binding in tumor tissues under different experimental conditions and for different antibodies
Antibody	Immunoreactivity	125I-[Tyr3]-octreotide autoradiography
		No or low receptor expression	High receptor expression
UMB-1 (PC-C)1)	0–10% of tumor cells stained	37	7
	>10% of tumor cells stained	2	43
	Staining intensity 0, 1+	31	2
	Staining intensity 2+, 3+	8	48
	No tumor cell staining	26	1
	Any tumor cell staining	13	49
UMB-1 (MW-U)2)	0–10% of tumor cells stained	38	9
	>10% of tumor cells stained	1	41
	Staining intensity 0, 1+	33	4
	Staining intensity 2+, 3+	3	49
	No tumor cell staining	16	2
	Any tumor cell staining	13	48
R2–88	No tumor cell staining	36	10
	Any tumor cell staining	3	40

B) Sensitivity, specificity, and positive and negative predictive values of semi-quantitatively evaluated UMB-1 immunohistochemistry to detect 125I-[Tyr3]-octreotide binding levels ≥ 3’500 dpm/mg in tumor tissues
Immunoreactivity	Sensitivity1)	Specificity2)	Positive predictive value3)	Negative predictive value4)
>10% tumor cells stained	86.0%	94.9%	95.4%	84.1%
Staining intensity 2+ or 3+	96.0%	79.5%	85.7%	93.9%
Any tumor cell staining	98.0%	66.7%	79.0%	96.3%

¹⁾Pre-treatment in pressure cooker in 10 mM citrate buffer (pH 6.0)

²⁾Pre-treatment in microwave in 5% urea buffer (pH 9.0)

¹⁾Sensitivity: true positive rate, fraction of correctly as positive diagnosed cases of all truly positive cases

²⁾Specificity: true negative rate, fraction of correctly as negative diagnosed cases of all truly negative cases

³⁾Positive predictive value: fraction of all truly positive cases of all positively tested cases

⁴⁾Negative predictive value: fraction of all truly negative cases of all negatively tested cases