Lung tumor promotion by chromium-containing welding particulate matter in a mouse model

Table 2 Severity scores for abnormal morphological findings and number of microscopically observed lung lesion types in A/J mice following exposure to GMA-SS welding fume PM at 30 weeks post-initiation with MCA or corn oil

	Lymphoid	Welding-fume	Preneoplasia	Adenoma within	Adenoma	Adenocarcinoma	Carcinoma
	infiltrates ^*	laden cells ^*		preneoplasia
Corn oil/Sham	0.25 ± 0.07	0.00 ± 0.00	5	2	2	0	0
Corn oil/GMA-SS low	1.79 ± 0.07^**	2.12 ± 0.04	1	0	3	1	0
Corn oil/GMA-SS high	1.84 ± 0.06^**	2.29 ± 0.07^#	0	1	4	0	0
MCA/Sham	0.15 ± 0.00	0.00 ± 0.00	16	5	34	0	1
MCA/GMA-SS low	1.44 ± 0.08^**	1.90 ± 0.05	61^**	17^**	70^**	4^**	0
MCA/GMA-SS high	1.57 ± 0.06^**	2.12 ± 0.06^#	65^**	9	93^**	6^**	1

GMA-SS Gas metal arc-stainless steel, PM Particulate matter, MCA 3-methylcholanthrene.
^*Severity scores were average of the right and left lung lobe score and are presented as mean ± standard error, lymphoid infiltrates are peribronchial/perivascular associated lymphocytes, macrophages, and plasma cells. Severity was scored as: 1 = minimal, 2 = mild, 3 = moderate, 4 = marked, 5 = severe.
^** p < 0.01 - compared to the corresponding sham in the corn oil- or MCA-treated groups.
^# p < 0.001 - compared to the corresponding GMA-SS low in the corn oil- or MCA-treated groups.

ISSN: 1743-8977