460 individuals (106 [23%] males and 354 [77%] females) in 440 families had been diagnosed with 1,143 primary tumors distributed among 87 categories according to site and cell of origin. The most frequent tumor types are illustrated in Table 2 (comprehensive lists are provided in Tables S1 and S5). Representing 24.6% of the total, breast cancer was the most frequent tumor, and colorectal cancer was the second (9.9%). Prior genetic testing is described in Table S6, and reasons for non-detection of the relevant variant are illustrated in Figure 2.
Figure 2 Molecular Investigations Initiated by Clinical Services with Inferred Reasons for Non-detection of Variants
Table 2 Most Frequent Tumors and Tumor Combinations in the Series
Tumor Category Count Percentage (%)
>5% Total (n = 1,143)
Breast 281 24.6
Colorectal 113 9.9
Kidney 83 7.3
NMSC 67 5.9
Ovary 58 5.1
>1% Total (n = 883)
Breast-colorectal 51 5.8
Breast-NMSC 35 4.0
Breast-ovary 34 3.9
Breast-endometrium 33 3.7
Breast-hem lymphoid 26 2.9
Breast-melanoma 24 2.7
Breast-thyroid 23 2.6
Endometrium-ovary 19 2.2
Breast-kidney 18 2.0
Colorectal-NMSC 14 1.6
Breast-lung 12 1.4
NMSC-hem lymphoid 11 1.2
Breast-soft tissue sarcoma 10 1.1
Colorectal-endometrium 9 1.0
Kidney-pituitary 9 1.0
Kidney-thyroid 9 1.0
Melanoma-NMSC 9 1.0
The following abbreviations are used: hem lymphoid, hematological lymphoid; and NMSC, non-melanoma skin cancer (including basal cell carcinoma and squamous cell carcinoma).