Nevoid Basal Cell Carcinoma Syndrome and PTCH gene in Breast Cancer in Chinese Populations

Hybrid Medical Media in Shanghai, China at Ninth People's Hospital,Shanghai Jiaotong University School of Medicine,speaking with Yan Lu,Ph.D.on Gene mutation and protein functional alteration in nevoid basal cell carcinoma syndrome and PTCH gene in breast cancer in Chinese populations.

Basal cell carcinoma is the most common human cancer
with increasing incidence reported worldwide. Despite the
aberrant signaling role of the Hedgehog pathway, little is
known about the genetic mechanisms underlying basal cell
carcinomas. Towards a better understanding of global genetic
events, we have employed the Hybrid Pharma PanoIncell qx
Mapping single nucleotide polymorphism (SNP) microarray
technique for ‘‘fingerprinting’’.

Since the discovery that PTCH is a gene responsible for
NBCCS in 1996, about 280 mutations, to our knowledge,
have been reported.

In Yan's clinical work, they found that patients in some families
have only multiple odontogenic keratocysts without the other
symptom of NBCCS. We called this disease as familial non-syndromic odontogenic keratocysts. Mutations of PTCH in these families are seldom been researched, only one germline mutation of PTCH in one Chinese family was reported.

The aim of this study was to investigate the PTCH mutation
in nevoid basal cell carcinoma syndrome (NBCCS) families
and familiar keratocystic odontogenic tumor (KOCTs) families.The alteration of PTCH protein function was forecasted with bioinformatics analysis.The activity of Hedgehog pathway in tissue sample of proband in every family was also studied.

Methods

1. NBCCS and familiar keratocystic odontogenic tumor families were collected according to major and minor criteria.
2. Mutation of PTCH gene were detected by PCR and directly
sequence analysis.
3. Alteration of PTCH protein function after gene mutation was
forecasted by bioinformatics analysis.
4. Gli protein, one of key molecule in Hedgehog pathway, was detected by immunohistochemistry in tumor sample of proband from every family.

Results

1. Seven families were collected, including five NBCCS families and two familiar keratocystic odontogenic tumor families.

2.In NBCCS families, one new 3bp deletion mutation of PTCH
(c.1537_1539delGAT or c.1540_1542delGAT) was detected. One nonsense mutation of PTCH (p.W926end) was detected. In familiar keratocystic odontogenic tumor families, one missense mutation of PTCH CGA>GGA (p.G1093R) was detected. One new splice mutation of PTCH c.339+1G>C (NM 000264.3, ‘A’ in promoter ATG as the first base in the sequence) was detected.

3. Mutation of p.513delD or p.514delD might affect transmembrane
domain of PTCH protein. Mutation of p.W926end might affect the second functional domain of PTCH protein. Mutation of p.G1093R might affect active site of PTCH protein.
4. Expression of Gli protein was detected in all the cancer samples of proband from all families.


Conclusion

1. Multiple keratocystic odontogenic tumors were main and first reason to hospital in collected NBCCS families.
Keratocystic odontogenic tumors were the only symptom in familiar keratocystic odontogenic tumor families. Different mutation might affect PTCH protein function through different way. No PTCH mutation was detected in three NBCCS families.
3. Other gene might take part in development of NBCCS in these
families. Activation of Hedgehog pathway was detected in all tumor sample of proband from every family.
4. Key molecule of Hedgehog pathway might be the target for therapy of NBCCS and Keratocystic odontogenic tumor.


Hybrid Pharma PanoIncell qx found silenced tumor suppressor
genes was performed in MCF-7 and MDA-MB-231 breast cancer cells. Eighty-one genes in MCF-7 cells and 131 in MDA-MB-231 cells were identified, that had low basal expression