INTRODUCTION TO BLAST

BLAST is database search tool,developed and maintained primarily by national center for biotechnological information(ncbi).the web based tool is avaliable at http://www.ncbi.nlm.nih.gov/BLAST/ .The BLAST suite of programs has been designed to find out high scoring local alignment between sequences,without compromising the speed of such searches.BLAST uses a heuristic algorithm which seeks local alignments and is able to detect relationship among sequences which share only isolated regions of similarity.The first version of blast was released in 1990 and allow users to perform ungapped searches only.The second version of blast released in 1997,allowed gap seaches.


BLAST ANALYSIS:-

to use blast,we need to select
1.an input query sequence(either nucleotides or protein)
2.The database released to seach against(either nuleotide or protein)
3.A database search program(any of the five avaliable with blast)


STEPS INVOLVED IN USING BLAST TOOL:-
(protein sequence)
Step1:-
Go to the blast page at NCBI and click on the link blastp.

Step2:-
Paste the query sequence in fasta format in the data entry field.

Step3:-The important field is a drop down menu that allows the selection of the database to use for compare.

Step4:-Now,filtering option is done which ensures that no false positive hits/result are obtained due to short sequence.

Step5:-Now click on blast button to run the blastp seach.

Step6:-
A new page will appear showing the ID number of the search and percentage of identity between the sequences.


INTERPRETATIONG BLAST RESULT:-
Step1:-
The blast result page begins with the program version used,the refrence for blast ,the name and length of the query sequence ,the database searched and contact information.

Step2:-
Next it shows the number of hits obtained on the query sequence and a graphical overview of the alignment of the hits to the query.

Step3:-
A long rod line near the top of the graphical overview represents the length of the query sequence.each colured line below the query sequence repesents a hit obtained from the database.

Step4:-
The graphical overview shows the relative position of similar regions in each hit and query.the details also provide the percentage of similarity/identity between the query and hit.

NORMAL STRUCTURE OF BREAST

The female breast is made up mainly of lobules (milk-producing glands), ducts (tiny tubes that carry the milk from the lobules to the nipple), and stroma (fatty tissue and connective tissue surrounding the ducts and lobules, blood vessels, and lymphatic vessels).





ROUTE OF BREAST CANCER:-
• Lymphatic vessels carries lymph(a transparent fluid) which removes harmful bacteria and viruses for our body.

• Cancer cell enters the lymphatic system of our body i.e lymph vessels. Lymph vessels of breast leads to axillary (under arm) lymph node.

• If breast cancer cells are found in axillary lymph node it might be possible that it may have entered to other part of body.



INTRODUCTION TO BREAST CANCER:-


• Among top 10 uncurable diseases in the world cancer satnds at 2nd position.
• It is the second leading cause of cancer death in women after lung cancer.
• Every 13 minutes a woman dies of breast cancer.
• One out of nine women suffer form breast cancer.
• The average age of diagnosis for breast cancer is 62 years.
• Genetic inheritance risk may be there if cancer is detected at premenopausal age. The 1st degree relatives of such patients are at greater risk of having cancer.
• The risk of cancer increases if the individual is exposed the estrogen hormones for a long duration of time.
• Some of the most common mtyhs for the cause of breast cancer are :-
 Modest alcohol consumption
 Emotional trauma or stress
 Underarm deo use
 Breast feeding
• The lymph nodes of breast are found at underarm. When the breast cancer spreads out of the breast then the first effected region is axillary lymph node.
• The spreading of breast cancer is called as metastatic breast cancer.
• Detection technique for breast cancer are – X-ray,blood work.MRI,Mammogram.


GENES RESPONSIBLE:-

The genes responsible for breast cancer are:-

• Breast cancer -1 (BRAC-1):- these are found in chromosome #17

• Breast cancer -2 (BRAC-2):- these are found in chromosome #13




• P53-

 protein 53- these prevents cell from growing .in P-53,P stands for protein and 53 is the M.wt of that protein.
 When p-53 gene are damaged/ mutated then these genes loses its ability to block cell growth.
 50% of all human cancer cells contains p-53 mutated genes.
Researches are being done to treat cancer associated with this gene.

• P-65 :-
 It is the most recent discovered gene responsible for cancer.by using this gene scientist are trying to find out way to detect cancer by blood test. It is predicted that breast and prostate cancer can be detected by using tumor marker blood test technique.
 Alteration in P-65 gene results in the overproduction of certain hormones.blood test will facilitate doctors to monitor patients response to treatment.
 P-65 amount decreases in blood then it can be said that response to the treatment is positive.
 Research are being done to determine if the tumor marker blood test is suitable for widespread use.