GSTM1 and cancer: Studies comparing higher restrictive Hb thresholds (such as 5.0 mmol/L or 5.6 mmol/L) also did not report significant better outcomes regarding mortality, morbidity, quality of life, and admission to hospital [19, 30, 31].  Therefore, the guideline panel decided to suggest an Hb threshold of 4.3 mmol/L in children with cancer and cardiac and pulmonary comorbidities.