Table 1. Patient characteristics and MCPyV oncoprotein antibody status among 219 MCC patients.

A total of 219 newly diagnosed patients with MCC were followed prospectively, of whom 114 (52%) were MCPyV-oncoprotein antibody positive at diagnosis. Patients with a sun-protected or occult primary, higher stage at diagnosis, or younger age at diagnosis were significantly more likely to be seropositive, whereas immunosuppressed persons were significantly less likely to be seropositive. One patient lacked staging information.

	MCPyV Oncoprotein Antibody Status at MCC Diagnosis
	Seronegative (n=105)	Seropositive (n=114)
Characteristics	No. (%)	No. (%)	P-value
Sex			0.98
Female	44 (47.3)	49 (52.7)
Male	61 (48.4)	65 (51.6)
Age at diagnosis			0.01
≤65	35 (38.4)	56 (61.5)
>65	70 (54.7)	58 (45.3)
Immune suppressed			0.004
No	86 (43.9)	110 (56.1)
Yes	19 (82.6)	4 (17.4)
Primary site			0.03
Head & neck	25 (50.7)	34 (49.3)
Buttock	1 (12.5)	7 (87.5)
Upper Limb	45 (62.5)	27 (37.5)
Lower Limb	14 (46.7)	16 (53.3)
Trunk	10 (76.9)	3 (23.1)
Occult Primary	10 (27.0)	27 (73.0)
Stage at MCC diagnosis			0.001
I	60 (65.2)	32 (34.8)
II	7 (25.9)	20 (74.1)
III	35 (38.5)	56 (61.5)
IV	3 (37.5)	5 (62.5)