Table 2.
β-Catenin Gene Mutations in Skin Tumors Correlate with Matrical Differentiation and TCF-1 and MITF-M Activation
| Histologic diagnosis | C terminus β-catenin Abs % reactive nuclei | αABC pattern | β-Catenin mutations | TCF-1 % reactive nuclei | MITF-M % reactive nuclei |
|---|---|---|---|---|---|
| PMX | 80 | Loss | D32N(GAC-AAC) | 10 | 30 |
| PMX | 85 | Loss | G34V(GGA-GTA) | 30 | 60 |
| PMX | 85 | N+ | D32Y(GAC-TAC) | 0 | 40 |
| PMX | 85 | N+ | D32Y(GAC-TAC) | 20 | 30 |
| PMX | 90 | Loss | G34R(GGA-AGA) | 20 | 50 |
| PMX | 90 | Loss | 33 nt insertion after codon 32 | 5 | 40 |
| PMX | 90 | Loss | D32E(GAC-GAG)T41A(ACC-GCC) | 10 | 30 |
| PMX | 90 | Loss | D32N(GAC-AAC) | 20 | 40 |
| PMX | 90 | N+ | D32G(GAC-GGC) | 20 | 50 |
| PMX | 90 | Loss | I35S(ATC-AGC) | 40 | 40 |
| PMX | 90 | N+ | D32G(GAC-GGC) | 30 | 40 |
| PMX | 90 | N+ | D32Y(GAC-TAC) | 25 | 50 |
| PMX | 90 | N+ | D32Y(GAC-TAC) | 30 | 20 |
| PMX | 90 | Loss | T41I(ACC-ATC) | 30 | 40 |
| PMX | 90 | Loss | S37F(TCT-TTT) | 30 | 40 |
| PMX | 90 | N+ | S33F(TCT-TTT) | 30 | 50 |
| PMX | 90 | Loss | D32N(GAC-AAC) | 20 | 40 |
| PMX | 90 | Loss | D32N(GAC-AAC) | 40 | 70 |
| TE-MD (TE with matrical differentiation) | 40 | Loss | T41A(ACC-GCC) | 10 | 30 |
| SCC-MD (SCC with matrical differentiation) | 80 | Loss | S37F(TCT-TTT) | 10 | 20 |
Among 83 skin tumors tested, only 20 harbored β-catenin gene mutations.
These tumors included 18 pilomatricomas and 2 tumors showing peculiar signs of matrical differentiation (1 trichoepithelioma, TE-MD, and 1 squamous cell carcinoma, SCC-MD).