The primary factors that define this system of classification and prognosis are age at diagnosis (young suggesting higher numerical grade), GH/IGF-1 levels (high suggesting higher numerical grade), tumor granularity (sparse granularity suggesting higher numerical grade), invasion (invasive features suggesting higher numerical grade), and size (larger tumors suggesting higher numerical grade), specific mutations, receptor expression (low SSTR2 expression suggesting higher numerical grade), and markers (low p21 levels suggesting higher numerical grade) [4]. Here, IGF1 is linked to neoplasm.