Table 2.

A comparison of mutation frequencies and clinical features

BRAF mutant, n = 22 (37.3%)BRAF wild type, n = 37 (62.7%)PBRAF or NRAS* mutant, n = 40 (67.8%)BRAF and NRAS wild type, n = 19 (32.2%)P
Subtype
    SSMM9 (64.3%)5 (35.7%)11 (78.6%)3 (21.4%)
    NM4 (36.4%)7 (63.6%)10 (90.9%)1 (9.1%)
    ALM2 (9.5%)19 (90.5%)11 (52.4%)10 (47.6%)
    LMM7 (53.4%)6 (46.6%)0.0058 (61.5%)5 (38.5%)0.114
Sun damage
    Minimal2 (9.5%)19 (90.5%)11 (52.4%)10 (47.6%)
    Nonchronic10 (50%)10 (50%)17 (85.0%)3 (15.0%)
    Chronic10 (55.6%)8 (44.4%)0.00412 (66.7%)6 (33.3%)0.082
Age, y (±SD)62.0 (±14.9)67.2 (±18.7)0.14062.0 (±18.2)72.3 (±13.6)0.031
Sex
    Male11 (45.8%)13 (54.2%)17 (70.8%)7 (29.2%)
    Female11 (31.4%)24 (68.6%)0.28623 (65.7%)12 (34.3%)0.780
Breslow depth, mm (±SD)2.5 (±2.2)3.1 (±2.9)0.5052.6 (±2.5)3.4 (±2.9)0.148
Clark level
    I0 (0%)4 (100%)3 (75%)1 (25%)
    II6 (75%)2 (25%)7 (87.5%)1 (12.5%)
    III5 (41.7%)7 (58.3%)9 (75.0%)3 (25.0%)
    IV7 (26.9%)19 (73.1%)14 (53.8%)12 (46.2%)
    V4 (44.4%)5 (55.6%)0.286§7 (77.8%)2 (22.2%)0.161§
  • * Only BRAF exon 2 wild-type cases were analyzed.

  • NRAS exon 2 analysis was unsuccessful in three cases because of inability, despite several attempts, to amplify DNA with NRAS exon 2 primers.

  • These data includes 21 ALM that inevitably show minimal sun damage and have low BRAF mutation frequency. Revised P values that exclude ALM are 0.732 for BRAF mutants and 0.184 for BRAF/NRAS mutants (see main text).

  • § Small counts invalidated χ test, therefore thin (Clark I-III) versus thick (Clark IV-V) lesions were analyzed using Fisher's exact test.