TTF-1 positive small cell cancers: Don’t think they’re always primary pulmonary!

Table 1 Thyroid transcription factor 1 expression in pulmonary and extrapulmonary endocrine tumours

Authors	Carcinoid1		SCC
	P	EP	P	EP
Folpe et al[2]	27/60 (45)	ND	20/21 (95)	ND
Agoff et al[7]	ND	0/49 (0)	ND	7/16 (44)
Cai et al[8]	11/16 (69)	1/58 (2)	ND	ND
Du et al[9]	15/53 (23)	0/28 (0)	ND	ND
Kaufmann et al[10]	6/12 (50)	1/20 (5)	30/37 (81)	12/15 (80)
Lin et al[11]	13/30 (43)	0/95 (0)	27/30 (90)	ND
Oliveira et al[12]	19/20 (95)	0/39 (0)	ND	ND
Saqi et al[13]	8/15 (53)	0/63 (0)	ND	ND
Srivastava et al[14]	7/20 (35)	0/103 (0)	ND	ND
Cheuk et al[15]	ND	ND	43/52 (82.7)	21/50 (42)
Jones et al[16]	ND	ND	ND	17/44 (39)
Li et al[17]	ND	ND	ND	9/42 (21)
Lu et al[18]	ND	ND	ND	9/15 (60)
McCluggage et al[19]	ND	ND	ND	11/13 (84)
Yun et al[20]	ND	ND	ND	15/21 (71)
Ordonez et al[21]	ND	ND	27/28 (96)	4/54 (7)
Total	106/226 (46)	2/455 (< 1)	147/168 (87.5)	105/270 (39)

¹Typical and atypical carcinoids are regrouped in this category. SCC: Small cell cancer; P: Pulmonary; EP: Extrapulmonary; ND: Not done.