Fig. 2.

UCN-01 decreases pS6 in tumor samples and causes a dramatic response of chest wall lesions to therapy. IHC analysis of pS6 on tumor specimens collected at baseline (a) and 24 h post-UCN-01 therapy (b) from Patient 14, whose tumor carried a somatic mutation in TP53 resulting in a change from CGA (Arginine) to TGA (stop codon) at amino acid 306 (i). Patient 14 had TNBC to the chest wall and lymph nodes and a partial response for 18 weeks. IHC analysis of pS6 on tumor specimens collected at baseline (c) and 24 h post-UCN-01 therapy (d) from Patient 24, whose tumor was ER+ , PR+ , HER2−  and was wild type for TP53 by sequencing. Patient 24 had chest wall and lymph nodes metastasis and disease progression after one cycle of study therapy. Representative fields are shown for each specimen. Specimens from Patient 14 had pS6 intensity scores of 2 for both pre-treatment (a) and post-treatment (b), but the percentage of tumor cells positive for pS6 was significantly decreased, from 20% pre-therapy to 1% post-therapy. Similarly, specimens from Patient 24 had intensity scores of 3 both pre-treatment (c) and post-therapy (d), but the percentage of tumor cells positive for pS6 was significantly decreased, from 40% pre-therapy to 5% post-therapy. IHC analysis of γH2AX on tumor specimens collected at baseline (e) and 24 h post-UCN-01 therapy (f) from Patient 14 and at baseline (g) and 24 h post-UCN-01 therapy (h) from Patient 24 demonstrated more DNA strand double-strand breaks in both tumor samples following combination treatment. Photographs of metastatic breast cancer to the skin from Patient 22 taken at baseline (k) and following completion of 2 cycles of therapy (l). This tumor exhibited nuclear accumulation of p53 by IHC (j) indicative of mutant TP53. Patient 22 had metastatic TNBC to the skin and lymph nodes and experienced a PR for 13 weeks