Pulmonary inflammation and tumor induction in lung tumor susceptible A/J and resistant C57BL/6J mice exposed to welding fume

Table 4 Lung histopathology for A/J mice 48 and 78 Weeks post-exposure

	Exposure	n	Lymphoid Infiltrates*	Welding Fume-Laden Cells	Lung Tumor Multiplicity^†	Lung Tumor Incidence^‡
48 wk	Sham	21	1.08 ± 0.16	0 ± 0	0.55 ± 0.14	50%
	GMA-MS	24	0.30 ± 0.10	0.34 ± 0.10^§	0.38 ± 0.12	33%
	GMA-SS	20	1.23 ± 0.22	3.03 ± 0.13^§	0.75 ± 0.15	65%**
	MMA-SS	24	0.90 ± 0.16	0.67 ± 0.13^§	0.38 ± 0.12	33%
78 wk	Sham	19	1.53 ± 0.29	0 ± 0	1.47 ± 0.33	68%
	GMA-MS	20	0.78 ± 0.24	0.15 ± 0.07^§	1.40 ± 0.32	75%
	GMA-SS	16	2.53 ± 0.36^§	1.12 ± 0.17^§	1.94 ± 0.38	88%
	MMA-SS	20	1.70 ± 0.27	0.55 ± 0.19^§	1.85 ± 0.46	75%

*Perivascular/peribronchial associated lymphocytes, macrophages, and plasma cells.
^†Average number of tumors/preneoplastic lesions per lung, includes mice with no lesions.
^‡Percentage of tumor/preneoplasia-bearing mice out of the total. ^§Significantly increased compared to sham (p < 0.05). ^||Significantly increased compared to GMA-MS and MMA-SS welding fumes (p < 0.05). **Significantly increased versus GMA-MS (p ≤ 0.05).
Note: Abbreviations are GMA-MS-gas metal arc-mild steel, GMA-SS-gas metal arc stainless steel, or MMA-SS-manual metal arc stainless steel welding fume. Data are mean ± SE.

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