CCND1 and breast cancer: Some examples of these genes are: PIK3CA (altered in 30% of tumors), PTEN (altered in 16% of tumors), TP53 (altered in 41% of tumors), MYC (altered in 20% of tumors), CCND1 (altered in 16% of tumors), ERBB2 (altered in 13% of tumors), and GATA3 (altered in 10% of tumors), as reported in patients with early breast cancer [10].