Table 6. Comparisons of the MM-bone model outcomes under the condition of P_MM = 0.055/day with experimental observations.

	Stage I/II		Stage III
	experiments	simulations	experiments	simulations
RANKL	1.62-fold [70]	1.75-fold	2.65-fold [69];2.26-fold [70];13.5-fold [71];15.67-fold [72];	4.35-fold
IL-6	2.6-fold/4.22-fold [75]	3.55-fold	9.79-fold [75]	10-fold
OPG	↓ [69];↑ [88] 1	↓	0.71-fold [73];0.73-fold [38];0.82-fold [74];0.59-fold [69]	0.69-fold
OBa	↑ [67], [68], [89]	↑	↑ [67], [68], [89]	↑
OCa	↑ [67], [68], [89]	↑	↑ [67], [68], [89]	↑
Bone turnover	↑ [67], [68], [89]	↑	↑ [67], [68], [89]	↑
Bone volume	↓ [67]	↓	↓ [67]	↓
MM cells	3-fold [67]	↑	Up to 6-fold [67]	4.48-fold

Note 1: Clinically, it is observed that serum OPG concentrations decrease at the early stage of MM disease [69], while it is recently suggested that serum OPG concentrations increase compared with healthy controls [88]. The exact reasons to cause the different observations are still not known. Possibly, OPG is produced by various skeletal and extra-skeletal tissues [90], leading to serum OPG concentrations do not reflect its availability in the bone microenvironment [88].

Note 2: All the ratios of experiments are obtained by comparing with healthy controls, whereas all the ratios of simulations are obtained by comparing with steady state of the normal bone model.