A statistically significant increase in PBSC collections was also obtained in patients mobilized with G-CSF plus plerixafor and with PB CD34+ count < 20 × 106/L on day 4.43 Taken together, these results provide a clear example of the potential of ‘early intervention’ with novel strategies to rescue cancer patients who can be considered ‘proven poor mobilizers’ as they have < 10–20 × 106/L PB CD34+ cells at the peak time of mobilization after G-CSF mobilization. Here, CD34 is linked to cancer.